He needs a good stache, but since we're using first person right now he might not even have a head in the current version of the game.
They called it the "Pixar topology" but I've seen some variations, here are some reference images, I went through some iterations on the topology of those four limbs and eventually got a result that I thought was working decently.
"Pixar knees" applied to the model.
I implemented a set of control rig separately for the upper and lower body in Unreal Engine so that I can record the animation montages inside UE's built-in Animation Mode.
more details about the Animation Mode here:
On the left is one section of the structure below, which allows one control key to move 5 (attached) fingers at the same time. Every finger is built of 3 connected bones.