Did you try changing all the facial structure codes to 00 in all the slots? Legends have no facial structure code because the model has been set, but generic faces can be edited. So my guess is, when you put a cf on a generic that has numbers in the facial structure code it will warp the cf head. Like, Elway's jaw will be too short and his forehead is stretched out. Just a thought. My 360 red ringed, so I can't test for myself or else I would have.
the facial code in like 4 slots long but if you put 2A 00 2A 00, you want hvae a problem with the face until u edited which you have to press Y to fix his face