This is actually Barnett's third failed drug test. Back in late 90's he tested positive for steroids but it was just for an informative survey so he was not in any trouble for that one. The second time was after the fight when he beat Randy for the heavyweight title. This the third time he should be baned from MMA forever.
Kimbo is no mma fighter but neither is Brock Lesner. I think Kimbo will knock Brock out in the first round if they fight. Fedor would beat both of them.