Canelo has the chin and power to be a serious problem but he isn't the kind of fighter to jump on Hearns the way Hagler, Barkley, Roldan or even Kinchen did. While he does have the defense to survive into the later rounds if Tommy blows his load he won't be able to capitalize on it since he doesn't have Leonard's stamina or footspeed. The hitman by MD. I would say UD but we know how Canelo fights go.
If Tommy stays on the outside and boxes, he wins easy. The problem with Tommy is sometimes he let's himself get pulled into a brawl when he shouldn't. Canelo is a great counterpuncher and is dangerous if Tommy is over aggressive. Tommy should win via decision.
Tommy's jab can win this along with the threat of his right coming behind it. Canelo has always fought in spurts rather than a steady attack. For Canelo to win Hearns would have to make a mistake and get clipped. I don't know if Alvarez hits hard enough KO Hearns. Hearns by dec.
I think 160 would be the best weight to match them. In a 12 round fight, i don't see Canelo closing the distance on Tommy. Canelo isn't Hagler- he isn't going to jump on Hearns. Canelo is a more cautious boxer than Hagler and slightly more "polished". If Tommy uses his jab and the ocassional stinging right, i think he wins a clear decision. Something like 8-4 or 9-3. But if Tommy decides to trade, Canelo could stop him. I pick Hearns by decision.