Being generous and making him a 3:1 favorite for every fight, which he wouldn't be, gives him a 13% chance of pulling it off.
In a vacuum he's a favorite over all of them. Fighting them all in a row, he might incur a loss or two, but he'd still have a winning record. Prime Mosley would be the toughest fight for him of the list, at 135. Taylor gives him a tough fight, but in the end Pernell's higher ring IQ should win out. Whitaker is a terrible match-up for Locche. Pea wins that one clearly. Tszyu is plain and simple not in Whitaker's league. That would be a shut out. And Ennis has proven nothing to pick him over Whitaker.
Oops, I forgot about Pryor. I take back what I said. Pryor's the toughest match-up for Whitaker, not Mosley. I've always felt that even in that fight though, Whitaker ultimately outclasses Pryor. A case can be made for the Hawk though. So, essentially: Pryor: 50-50 Mosley & Taylor: Live underdogs. Locche & Tszyu: Substantial underdogs. Ennis: Too unproven to even handicap how the fight would go.
Yes, especially if spread a little. Pryor is the toughest fight. He'd throw caution to the wind and would be tireless. His wild swings and unorthodox angles would lend some trouble to a great technician like Whitaker. He'd be able to force Nell out of his comfort zone. Would it happen often enough? Probably not but he's in there.
Personally, I believe Pryor is the one to beat him. Pryor hit like a mule kicks, power in both hands, had great endurance, was very quick of hand and foot, attacked from angles that would be foreign to even Whitaker, had a great chin ( If Cervantes, Johnson, Kamada, and Arguello couldn't seriously hurt him, Whitaker wouldn't either) And was totally relentless, all the ingredients needed to beat Pernell Whitaker. Love Whitaker, and everyone else on your list I believe he'd beat, some like Ennis and Tzsyu he could embarrass.