To offer an opinion I prefer core assets to match up rather than using in app solutions like re-targeting. Re-targeting is handy but with due respect it is a band-aid available as to when there is no other option and is a lot more pain involved down the road as compared to the time to match things up.
Retargeting on the other hand is not as complicated as it sounds with the right tools that does all of the work for you as a batch process. In this case I use MotionBuilder and as a tool for retargeting you set up input character A into character output B, push a button, and go for coffee.
You could take the entire CMU motion capture database and convert it to Blue man in a few hours and most of that is figuring out where to put it.