Hellooooooo.
Well i actually seen a few screenshots around , dont know if fake ones or real , of a mugenized fighting scene between 2 characters from that game. I had the FB game and played the heck out of it. Those characters are or would be quite the workload to try and reproduce a bonifide character for mugen since those characters dont even have regular spritesheets of some kind. They dont even have moves other than their specials and such. No basics required for mugen. Heck i aint sure those are even sprites! Pixels i mean.
So unless i think a really amazing animator can snatch those characters out, refit them to function on a regular 2d plane, and the use a great animation tool/program and give the characters "bones" and animate every frame....something like Spriter pro. Then i dunno. Would be awesome tho if done. Check around to see if they are ripped out from game and see if can do somethin with those. If can.