“…how to easily align two bones on top of each other in Pose mode…”
Now, I am not a Rigger and I don’t know 3ds Max, but couldn’t you just use a Copy Transforms Bone Constraint and change between an Influence of 0 (original LocRotScale) and an Influence of 1 (LocRotScale of Target Bone) for that?
As for the rest of the question, I don’t understand what you want to do exactly, sorry.
