The way you worded it sounded like you wanted to move the characters based on real life physical constraints. In other words, skeletal structure, muscles power, etc. How people move in real life.
As for what you posted, it looks a lot like IK.
However, if you’re going to be controlling what joints move with the mouse and don’t wish to worry about collision, then you can just move them in code by editing the bones rotation and what not.