They were all put in as opponents for Tyson before he was and wouldve probably all been thought of as potential opponents at that time before Buster. Nobody and i mean Nobody was saying, "Hang on a minute, Tysons' not a legit champ , he hasnt faced Buster yet'.
Hubris was Tyson's biggest enemy and I don't think anything could have kept it from creeping in -- dropping Rooney is probably an indication that he didn't want to be told what to do in training and didn't want someone around who could keep him in the gym and didn't want to listen ... but the fact that he didn't go find another qualified, world-class trainer makes it clear that he was going to do what he wanted to do, when and how he wanted to do it.