Interchangeable body parts (3D)

Godot Version

4.2 C# (though I don’t need language-specific advice)

Question

Suppose I had many models of creatures with different proportions and looks/feel. Suppose also that these models were split by body part – 2 arms, 2 legs, 2 feet, 2 hands, a head, a body, etc. What would be the easiest way to build a system where these models could have interchangeable body parts, including maintaining any per-body-part animations? How would you ensure that the points at which the body parts connect remains the same, even if they move or rotate during the course of an animation?