Proper/Optimal way to do TPP/FPP...?

I think what I’d like to know is how to swap out skeletal meshes at run-time, and if there is a way to retain 1 set of animations.

i.e 1 Full body char mesh for TPP and 1 without a head for FPP, but having just 1 set of animations for them both, maybe being able to turn the head bone off as well during run-time.
2 seperate anims could get costly, so maybe an opportunity to cheap out xD