Out of all his contemporaries, Sullivan seems like he'd have the best chance against Wilder on paper. He was apparently a Tyson\Dempsey type fighter, who would fight out of a low crouch and use excessive feinting and head movement while rushing for an early KO. If Sullivan was in any way as good as the people from his time said he was, chances are he'd be a bad matchup for Deontay. No way to know for sure though