I think the body parts can also merge into “equipment slots” system. For example，a normal human will look like this：
- brain, a organ , offers a brain slot, provide mind .
- head, a container (also a body part ), offers a body part slot, a container slot and a head slot.
- hair, a body part , offers a fur slot.
- body, a container (also a body part ), offers a body part slot, a container slot and a body slot.
- heart, a organ , offers a heart slot, provide energy . (same as other organs)
- arm, a body part , offers a body part slot, provide motion .
- hand,a body part , offers a hand slot, provide control .(same as legs and feet)
- eye, a body part , offers a eye slot, provide vision .(same as other features)
According to the “Skins and Custom Player Models” part, player can custom them body. So a universal clothes may not suitable. If possible, just let players customize armor’s size and shape, then do a “2d collision check” with their body、arms, and maybe tail or wings.