Heya! Thanks for all the likes! 💚
To answer your question: I already pulled
design elements from AC and DoC and even Rebirth / Remake in some of the sketches... that's why Chaos Vincent looks the way he does. I started before DoC had been released, which is why
this and
this 2005 page got redraws. Back in those internet cowboy days I worked on character design by popping in my playstation CDs and pausing the game to look at these characters while in the battle screen, LOL. Advent Children was both a shock and a major upgrade, and DoC doubly so! But the good kind. I just wish Vincent would stop changing his boots, prosthetic arm, and hair, haha.
As for using story elements from AC and DoC... naw, not really. While I actually really enjoy DoC storywise, I think there's too much canon divergence in this story (especially the Sephiroth being Vincent's son thing) for it to mesh well with the later works. So yeah, this is kind of a stand-alone universe. (Or one of the many multiverses that SqEn seems to be pushing as canon for the Remake / Rebirth stories!)
As for Mako poisoning: I think whether or not you get magic skills would depend on whether or not you had inherent magic skills before you got the mako poisoning. I imagine Aerith, Nanaki, and maybe even Yuffie (ninja magic!) would be able to develop into monsters with monstrous magic skills, while people like Cloud, Tifa, Cid, or Barret would just become plain old monsters. I don't think Vincent can get mako poisoning, he's already been killed and mako resurrected by Shinra! But I imagine he'd have a harder and harder time controlling his 4 inner monsters, and physically, I suppose given enough time, he might start looking more and more like Galian Beast.
But in a nutshell: any living organism that absorbs too much mako will eventually turn into some sort of monster. It ain't healthy!
Cheers