Imagine thinking he'd beat Gomez. Morales, and Pac are made to beat him, he had huge issues with southpaws, I'm not sure he'd even beat Hamed.
Morales. The better offensive fighter, with the power too. He would find Rigondeaux with that educated right, and eventually stop him. Rigondeaux would definitely have his moments early though, troubling Morales with his pivots and left. Troubling fight for Morales, especially if he decides on the wrong gameplan. Rigondeaux might quit before he gets stopped though.
I'd favour Fenech as well (though not a southpaw) as Xplosive said. Size, strength, workrate and power would be too much ( and Donaire aside from one shot power couldn't match Fenech in any of these categories and Fenech hit solid enough at 122 anyway). Fenech would have crowded and monstered him. A clear Fenech UD is my guess unless Rigo quits. Rigo does have the defensive ability to physically last the distance with anyone but perhaps not the psychological ability. Rigo was/is a huge talent but his career has been frustrating and I'm tipping we never saw him at his best in the pro ranks anyway. So to be fair we have to take this into account.