Buddy Baer wouldn't have much chances against any of K2 Brothers. Maybe if he faced young and overconfident Wladimir (I think Buddy was better than Purity), but prime for prime Wlad is way too good for him. Max could be interesting, he fought the best when he had speed advantage and that would be the case here. He could stop Wladimir, although I wouldn't bet on it. He could also overwhelm Vitali to a decision win, but he'd have to be highly motivated (like against Schmeling). Baer's lack of interest in half of Carnera fight wouldn't work here.