But seriously, I thinks it's possible... hell, it's Mugen, you can probably combine characters, yeah... the problem is that it's a load of work to do that.
But I realy don't know much about that, so I can't go into to much detail on that subject...sorry

Hope, I helped

Or something similiar?

OH and I just remembered of a good example of combined characters, as in sprites UBU by Aiduzzi where the creator junctioned Gen's head from SFA/SFZ with Fei Long's torso from SFA/SFZ with I belive it´s Yamakazis leg's from KOF.
And as in powers I saw an Akuma edit named Ogre where he can use a variety of abilities from diferent characters.
Maybe you shold check them out to get the idea...