This should be pretty short by my standards since there isn't much to cover. So for me, Oda did a great job of distracting us at some pretty key breadcrumbs in chapter 1013. Essentially, Oda is having all of the direct soul Homies reflect different parts of Big Mom's life and the different personalities.
First, we have Zeus who reflects the tiny bits of the young Lin Lin we see before her 5th(?) birthday. Because of the naivety and only being concerned about food, it isn't a surprise that Zeus is an airhead the makes mistakes over and over, and becomes dispensable.
Next, we have Prometheus and his recent desire for a girlfriend. Prometheus is the serious one that wants to buckle down. To me, the puberty part overlaps Big Mom establishing herself as a legitimate New World powerhouse. Maybe she has a crew prior to her children, but the no nonsense drive is what led her to rise to power.
Lastly, we have Hera. The proud female that knows she can just manipulate men. Despite Big Mom's eccentric character diversion (by Oda's patterns, it is what happens when people do not achieve their dreams), her young appearance matches the play girl that legitimately established the 100+ children.
I am not skipping over Napoleon, but it is a little harder because we do not really have him talk/get to see any personality. The main "personality" we see is the berserker/violence or fight loving "crazy face" we see when he is a sword. His normal state of a captain's hat could represent the adult Big Mom that is the "best strategist in ALL of One Piece". Plus, the violent side reflects how Big Mom loves a good fight just as much as Kaidou.
I don't think it is a trend that the power scale increases with the progression of Big Mom's personality. With the B.S. of blades with haki...maybe Napoleon is the strongest soul Homie. However, the progression of Zues -> Prometheus -> Hera is undeniable.
All of the cry-faces of Zeus is not only important for the chapter/character development before his likely death, but it also reflects the loneliness of losing her home. The lost/depressed Lin Lin is susceptible to just follow Streusem and turn evil. Oda reinforcing all of the different stages of Big Mom's life is why we need to complete her flashbacks. We need answers for multiple parts of her life and potentially each of the stages that are reflected by soul Homies.
It is terrible literature to just disrupt the flow and throw in Big Mom flashbacks in the midst of a Kaidou focused arc. Even if Big Mom does not leave, we need a conclusion to the Kaidou-arc and have a separate Big Mom arc so that we can build her up for defeat. We didn't even have this for Kaidou, and this is a separate "theory", but the short fourth act implies we might see Kaidou's build up after his defeat (since it ties to the history and resolution of Wano Kuni becoming open to the world).
How Big Mom gets her soul abilities is likely one of, if not the biggest Devil Fruit questions. We weren't shown any fruit on purpose in the birthday scenes. But, I have to think Caramel's shady business has ties to future parts of the plot too (John Giant being an admiral candidate is HUGE).
Just like Wano Kuni is directly tied to the end of the series, so will Big Mom's flashback. Skipping over this ruins the rest of the plot. Just because we can see the breadcrumbs in place, Oda purposefully keeping every little detail completely open ended is why we still have no idea what is actually going to happen.