It uses similar techniques as games like TABS or Human Fall Flat.
It's designed to be as simple as possible.
TL;DR: a PID controller applies forces to ragdoll to make him follow static animator (skeleton in the gif below).
AnimationFollowing.cs applies animation following.
MasterController.cs contains all 3rd person controller logic. It makes sure static animator can't move too far away from ragdoll.
SlaveController.cs controls behaviour of animation following in real time. It makes ragdoll loose strength when colliding with other objects.
Work in progress.