None of these guys could have beat Quarry, They do not have the skills or power including Baer! these guys fought and beat the best white guys in the world during their careers OK, Jerry beat the best black guys in the world during his career (or at least 38-7-1 w/23 KNOCKOUTS). None of these guys would have fared better than Quarry, vs his opposition. Its not a matter of race, its a matter of ability! and differant era. Joe Louis was great in his time, Muhammad Ali would have turned him into a pretzel. Joe Frazier, very underestimated Champion.
In no way saying that Braddock would be beat Quarry but Jim wasn't that bad. He was tough and had a good punch as Joe Louis found out. He floored Joe, if he landed the same on Quarry, he would have a shot. Personally I think Quarry has wars with Baer and Sharkey, two good fighters.