Motionbuilder Skeleton vs. Control Rig

[alex.sz]

Hi my friends. I'm quite new to Motion Builder so I guess this is a quite basic question.
I'm working on retargeting MoCap files in Motion Builder. So I got several BVH files where I first define the skeleton. I often see in tutorials, that people afterwards apply the control Rig to the Mocap file and use this as the source of the character (that also gets a control rig?). Why don't you just define the skeleton for both and use then the bvh as source, without the control Rig? What's the benefit of using the control rig?

Another simple question: I really like, that i can merge all the bhv files in one hierarchy, to just define it once. But it would be also cool if I could bring several bhv Files into MB, place let's say 5 identic characters next to each other and watch the retargeted animations at the same time, withoud doing the definition of the skeletons for each bvh file. Is that possible?

Thank you very much!