Foster tended to lose to top tier heavies, even those who were cruisers. Patterson was one of the best 176-200 pounders to ever live up to this point. Him beating Usyk at cruiserweight isn't completely off the table (I'd pick Usyk to win). Patterson by KO over Foster.
The Foster that fought Ali and Frazier was better than the younger version who lost to Terrell and 2 other contenders. He was manhandled by Ali but actually got in a number of shots. He d be landing those in greater number on Floyd who didn’t have the best chin. But Floyd was fast and powerful he could KO Foster. This is close to call but I ll go with Floyd.