Cleverly won't stand a chance against Bute. His style is all wrong, he has no power to speak of and he's 2 levels below. There's a reason he's fighting cans.
Thing is, Bute didn't try to trade with Froch. He played to his own strengths and tried to get in with fast shots and get out again. Problem was, Froch had clearly worked on his own hand speed and Bute couldn't get his punches off without getting countered. Ward was a level above Froch, that's why he beat him, and Froch was a level above Bute. It doesn't matter how Bute fights in the rematch, he's going to get caught and doesn't seem to have great punch resistance, so the end result will be the same. I'm not sure about Clev v Bute, but at light heavy I think even light punching Cleverly will bash Bute up. Bute fell apart mentally against Froch too, he may well be never the same again (Jeff Lacy?). Clev isn't great, but Bute is worse...