Hello,
Just throwing this out there because it could be useful for someone. I wrote a “retargeter” script to automatically load a folder with animations over a new character. It’s over at github: https://github.com/eksod/Retargeter
It basically needs just the new character already characterized and a folder with animations in .fbx or .bvh. If there’s a character on the animations the better, if not it characterizes the loaded animation, so this animated character serves as the input for the new character. This is the only tricky part, if there’s no character on the animations all of them must have a tpose on frame 0, and ideally have all bones above ground (above 0 y). If the characterization is not correct neither is the retargeting, obviously.
It’s better to try first the retargeting with a couple of animations, and tune the retargeting options for the character. These options are saved with the character, thus being used for all other animations.
I’ve also wrote two blog posts about it, a simple resumed one, and a long one for new animators, sort of explaining what is retargeting and how this stuff works in Motionbuilder.
I’ve tested with data from work and also with cgspeed version of the bvh and fbx from CMU mocap database. So yeah, if you wanna play, there are 2600+ animations you can quickly load over your characters now. 
If anyone find a bug, or any comment negative or positive, please let me know.