Roy never showed a shaky chin in his prime; Hearns did - and at lower weights against lesser punchers.
Highly unlikely. I think Roy would have a relatively easy time with Tommy. Four or five rounds, maybe less.
Close your account. This fight wouldn't even be competitive. RJJ would clown Hagler worse than he clowned Hopkins and Toney, and Hearns worse than all three of them. Easy, easy night for Roy. RJJ is the best MW who ever lived, and 2nd place isn't even close to him.