I don't think you can edit the players likenesses if they are on current teams, generic or not. I think you can release them and bring in a player you created from your free agency, God I hope so. But they already removed Export Team from associaton, so people can't make official retro rosters and share them now. I guess it's been in the game since 2k6. They took it out for 2k13 for some reason.