Model Layers And Animations Don't Sync, What Are My Options?

As the title suggests I'm at an impasse, I can't make this mod without severe alterations to the main concept without the ability for Model Layers and Animations to sync. My question is what can I do here? or am I just cooked?

I'm trying to stay away from coding outside of something that could be done in a single Mixin.

I need the model layers because I'm trying to make a MCA style NPC that changes only parts of its texture at a time so I can mix and match.

Thanks in advance!