OK, so the rule isn't that Devil Fruits grant 2 sets of abilities - passive and active. A more accurate way to describe it would be that Devil Fruits grant abilities, and that all abilities can either fall into the "active" or "passive" categories. The distinction is that to frame it your way would be to commit to every DF granting at least one active and at least one passive ability, when I don't think that's the case. I think there are some DFs that are entirely active, and some that are entirely passive - even if we haven't seen any so far (though as I've indicated I think we have of both), they are certainly possible to conceptualise - but that in the majority of cases there are a mixture of both.
I also don't think that you have correctly understood what's meant by "active" and "passive" because of the way that you've spoken about Luffy here. An easy way to understand it is that "passive" abilities will still be accessible when the user('s body) is perfectly still - and can be applied to being asleep if you like. Conversely, active abilities can only be activated by the user willing the thing to happen, and will never be able to be accessed from the environment. Active abilities are usually binary (I actually can't think of any that aren't) - they are either on or off - and they can't be "trained" in and of themselves.
For example, when Mr. 1 is asleep, he will still have a metal body. But there's nothing you can do to Mr. 1 to make him unwillingly turn his arms and fingers into blades. You can feed Magellan as much poison as you like while he sleeps (ignore the difficulty of eating while sleeping for this example - if you don't like it imagine he's been tranquilised as the stuff is being pumped directly into his stomach/blood stream), but you will never get him to actually create poison.
There's a bit of ambiguity surrounding things like people using their DFs reflexively, but we will count even those as active - imagine passive will also work on someone who's been lobotomised.
So let's get to Luffy. From what we have seen Luffy has absolutely no active DF abilities (this actually may change with recent revelations from the manga, but let's wait and see how that develops). Rather, he simply utilises his passive rubberiness in all of his fights. You cite the Pistol and Balloon as examples of active abilities, but they aren't. The Gum Gum Pistol is an ordinary punch that utilises Luffy's rubberiness to stretch out and increase in power. Hypothetically, if he was under enough sedatives, you could completely recreate the stretchiness of the Gum Gum Pistol in Luffy's sleep by manually pulling his arm back. Luffy (to our knowledge) isn't actively altering the stretchiness of his body in order to control the punch, but rather he's using his practice with his physical body (which we know from his training it as a kid). Luffy's problem as he was training the Pistol wasn't "Aw man, I made it too stretchy that time", but "Aw man, my punch wasn't strong enough that time". He wasn't learning to directly control his rubberiness, but rather he was controlling his strength to maximise its effectiveness with the rubberiness.
Similarly, with the Balloon, it's not like he can just sit still and activate the Balloon. He has to manually inflate himself by sucking in a whole lot of air. The "active" component (sucking in air) has nothing to do with his DF - he's just again using his passive rubberiness to create the Balloon. Further, we could hypothetically recreate the Balloon in Luffy's sleep by pumping him full of air.
If Luffy could, without moving a muscle, change his elasticity, then that would be an active ability. Another *possible* active ability of Luffy's DF is making his blood pump with Gear 2nd, but this is something I've seen as an oversight of Oda (like how he doesn't immediately deflate after activating Gear 3rd due to the bite-holes in his thumb).
Okay, this clears up my misunderstanding completely. I do see your point but I would like to make a small correction on the perception of my own view. I wasn't actually suggesting that every user necessarily has to have both a passive set or an active set but by suggesting that the active set was always based on the passive set, I was ruling out the possibility of there being a fruit with only an active set of skills. After your explanation though, I now see that I was wrong to think so. Especially so because you even offer examples, like Mr.3 and Newgate (many others also come to mind: Foxy, Kanjuro, Sugar, etc). Now I'm liking this sort of classification even more. Brook could still possible be a contradiction but I'll get to that shortly. For now, I'm really liking this sort of classification. Have you posted a theory about it here or was that back in OPF? If it's not here, I'd really like to see it if and when you have the time to write it. So if / when you write it, please do tag me.
Just to throw my two cents in the meantime, I don't think Luffy's gears would fall under his active skillset. Putting aside the validity of the gears themselves, (like how he doesn't immediately deflate after using gear 3rd, like you say) Luffy could be "forced" into his gears in his sleep. Use his legs as pumps to mimic his motion for gear 2nd, pump his bones with air for gear 3rd and pump his muscles with air for gear 4th. Well, gear 4th would probably not work quite the same but that'd be cause of the lack of haki.
SO, let's circle back to Zoans and Chopper. First I'd like to clear up a misunderstanding that I had a long time ago: Except for in some very special cases, Devil Fruits do not replace the properties of the eater, but rather they add to them. If Chopper was a reindeer who "turned into" a human, then you're right - he should have turned in an actual human. But he didn't "turn into" a human. Rather, he is a reindeer who "gained the abilities of" a human. He didn't lose anything: only gained. Now, it can get VERY technical with some details, but I'm talking about the general rule. We can't think of Chopper as sometimes reindeer, sometimes human, sometimes hybrid. Rather, he is always a reindeer + human entity. This is why he still retains his human intelligence in his reindeer form, and some of his reindeer furriness in his human form. At all times, and in all forms, he has all his reindeer faculties, and all his human faculties. I actually think that it was genius how Oda has consistently been able to apply this formula over all the Zoan types that we've seen, and especially in Chopper's case (to digress a bit, the reason it's so good is because Oda has given Chopper "perfect" humanity in terms of physique and intelligence. This is why he's able to learn and remember so much medical knowledge, and why he's well-built in his human form. If someone were to ask "What would happen if a human ate the Human-Human Fruit?", from watching Chopper I would say that they would become more intelligent and have all of their senses improved including their ability to focus. Basically they'd become a 'better' human).
Something else I'd like to touch on to hopefully add a bit of clarity to what I mean by "add to" vs "replace". One can reasonably ask (e.g.) "By this formula, how can Chopper have both a human nose and a reindeer nose at the same time?". And this is where the aforementioned technicality comes in. The physical appearance of his nose (and ofc the rest of his body) is dependent on the form that he's choosing to be in at that current time.
But his sense of smell is always the same, regardless of which nose he's wearing. He's always able to have the keener sense of smell of a reindeer. This applies to any property where the sense of the original eater is superior to the sense of the Zoan animal (or vice versa), for example the bloodlust of Carnivorous Zoans, and interestingly in Chopper's case as well, the Intelligence of the Human Zoan, and I think there is a neat explanation for this:
Both senses are retained, but we simply perceive only the superior one since it's the one that's actually used all the time. I.e. Chopper would never really have a reason to use his human sense of smell since his reindeer sense is stronger. One of the reasons I choose to say that both senses are retained rather than only the superior one is because "superior" is subjective as heck and it'd need quite a bit of explanation to justify how the DF power would decide which traits to override, and because where applicable, we've seen traits from both species come through in Zoan eaters. For example, Chopper can eat human food, but feels attracted to Milky, a Reindeer . It's not cut-and-dry, since she's a Reindeer Mink instead of an ordinary reindeer, and since it's possible that it may just be the case that the human food he's been eating is all edible for reindeer, but I would find it hard to believe that he couldn't still eat reindeer food (like vegetation), or be attracted to humans. So I think the best explanation is that he's got both sets of functions and senses accessible to him, but he (and all other Zoans) just synthesises them and uses whatever's most useful in the moment so we only perceive one.
I completely agree with everything here and have nothing to add. That being said, if it apparent from me referring to a Zoan's "semi" and "full" forms, I was talking about their active skill set. I'll to that in the next section, where you talk about it, but as far as their passive skill set / physique goes, I completely agree with and like everything you say here.
So with that background, let's get into talking about active and passive abilities for Zoans. Zoans all have a very similar active/passive skillset. Their active skillset is only in performing the actual transformations (granting them access to different physical faculties of their animal such as physique). Their passive skillset is the acquisition of the Zoan-species' senses. That's it. Senses here referring to the 5 senses, intelligence, and other base instincts like appetite and impulses. I am hesitant to say this, but it may also be the entire personality of the Zoan, because we know from Funkfreed and Mr. 4's gun that there is an animal personality that manifests when a personality-less entity consumes a Zoan Fruit.
It's quite an elaborate explanation, but the more we look at examples of Zoans I see nothing against this theory and a lot in support of it. I should probably make a thread for it lol
Okay, this is what I wanted to talk about regarding Chopper. So, generally speaking, a Zoan fruit user should have 3 forms: The natural form (0%), their semi form (0.1-99.9%) and a full form (100%). The percentages represent how much they actively tap into the powers / forms of their zoan animal.
So, to start with, we have their natural form. Based on the everything you've said about a Zoan's passive skillset and physique, their natural form would their default form, for which they don't have to transform into, which is a combination of traits and senses which are decided by the devil fruit. Based on what you said, it should generally be decided by whichever is most superior.
The there is a zoan user's semi form. Now, for every zoan user other than Chopper, their semi form seems to be set in stone. In other words, they can't control what percentage of their human / reindeer / etc part or what percentage of their zoan animal part they use. Generally speaking, it seems to be something along the lines of 50-50. Chopper however can control those percentages, and said control leads to his various points. For example, while he has the intelligence of a human even in his natural form, he once even had a "brain point", where I assume he consciously tapped more into his zoan animal part than his reindeer part. And then there are points like the "guard point", which focus more on his reindeer part rather than his zoan animal part. Well, everything I've said so far is nothing new. What I wanted to especially focus on is the next part.
Lastly, we have a zoan user's full form. When transforming into this form, the user's physique becomes identical with their zoan animal. Marco becomes a phoenix, Drake becomes a dinosaur, Sengoku a buddha, etc. And yet Chopper doesn't seem to have a full form and can't fully transform into a human. Practically speaking, we could even attribute it to mental trauma caused by all the discrimination against him from both races (which, along with the rumble ball, can actually be part of the reason he's so good at the "in-between" forms) but theoretically speaking, Chopper SHOULD be able to fully transform into a human in his full zoan form.
Incidentally, I'm not sure where to put his "monster point". It could be a semi form that focuses on his reindeer part for the most part or the devil fruit decided that his reindeer part was more prominent for his goals / whatever else criteria is has and instead of Chopper having the full form of a human, his full form is the monster point.
So, as I've already indicated, I think this is an exceptionally rare case where a DF eater doesn't discover an active ability until quite a bit later, or with some experimentation. You use Luffy as an example, but as I've already indicated I don't think that's accurate. BUT Brook is an accurate example, since him accessing the ice and turning into a ghost are active abilities (you wouldn't be able to get him to do them in his sleep) that he didn't discover until much later. The short answer is: I don't know. My personal inclination is to put it down to Oda just inventing these power later and it being a genuine issue (because as you say, DF eaters should know their active abilities fairly instinctively as we saw with Kaku and Kalifa, and we're given no reason in the story to draw a distinction between the instinctive active abilities and the discovered ones). To try to give it an in-story explanation, we could perhaps say that the eater only has vague perceptions about how to activate their abilities, and then only fully realises what they are after activating them, and then perhaps some of these vague instincts aren't fully fleshed out because they're not really distinct. It's super hazy, and I do grant you that it's a difficulty my theory (or any I think) can't address well.
Brook doesn't seem to be willing to give you a break mate, contradiction back then, still a contradiction now. Well, joking aside though, it really would be hard to explain. If I were to try and do so, the only way that comes to mind right now would be to suggest that Brook doesn't actually an active skill set.
Like Luffy's fruit turned him into a rubber man and we could stretch his skin in his sleep, we could say that Brook's fruit turned him into a "strong-soul" man and we could theoretically pull his soul out of him and he's still be alive and in control of it. And that the only reason that's not possible is not because it's active ability but rather, it's almost impossible because we can't interact with the soul's ethereal form. Someone like Big Mom, Law or Teach could do it though. Well, not Law cause he'd switch it with another but maybe Big Mom and Teach. As for his freezing abilities, we could say that if his soul was actually pulled out of him while he slept, it would emit a freezing aura all by itself (passive ability) and the only thing he actively does while fighting is apply that to his sword.
Seems just a bit forced I suppose but I don't see a better alternative currently. Well, that's just me though. If / when you write the theory, I look forward to seeing it mate.
I know you wrote this first and I'm getting to this last, but WHOOPS! Yeah haha now that you mention it I do remember our huge discussion about this theory. My bad :')
I've had lots of discussions about it over the years with a few different people so I tend to lose track lol.
No worries at all, there's also the fact that it had taken place quite a long time ago as well.