Hi ebbie273,
Wow… from a human into an animal or a zombie? Sounds cool. Maybe you can try using a morph targets. Morph target on material will change the skin, you can change the pose of the bones to account for biped human, on all fours for an animal and a hunched over and crooked pose for zombies … I think morph targets in combination with state machines, you will be able to achieve what you need.
In case you are looking for a C++ solution, check out USkeletalMeshComponent and USkinnedMeshComponent.
Thanks