- "nishys animations would change based on her overall size " : well yes, the animations will change, yet from your suggestion i'm now considering having a smaller difference (not full pose change), so that you can blend the animations based on it's size, thus having a slider as of sort for the size.
- "she has her own set of stuff is because of the size diffirence" : it's more about 3d skeletal and facial rigs used, which means that it's best to make new anims (and personally, i do prefer new/unique anims, it just takes time to make them). As an example for the technique your describing is the gang animation on female x 2 kobolds/wargs (mid sized males), since the game uses Nun x 2 males animation with nun having a taller rig then the other females (nishy,fapets..), thus you can see a bit of a stretch on their spines.
- "as you could toggle any of her sizes to make a rare animation" : if i got it right, you meant making more animations for each case/toggle and just switching based on toggles, but that would at least double my work so not sure. Something like this can be seen in Kelpie x Nishy (cow pose) and same thing but while Nishy is in futa state. On the other hand, i would first give a try to procedural animation. This is done with animation + in-game live IK, the system which i'm currently finishing for the upcoming game. Slavebar uses just animations + small extra things for facials and breathing, so it's not quite compatible. In next games (not sure if SB aswell) i'll try to use this technique more and see how it turns out.