Flowers has the best chance. Tackles with a nasty attitude and who can pass protect shoot up the ranks. If he declares and aces the combine and individual workouts, he could easily move into the first round. Nobody thought Ju'Waun James was a first rounder last year but so far he has graded out very well.
Greg Robinson had penalty issues at Auburn yet was selected second. And it's hardly true that Flowers punked Gregory of Nebraska. They seldom lined up against each other. When they did, both guys had some standout plays. Gregory bent Flowers backwards on one pass rush early in the game and knocked off his helmet on another. Later in the game Flowers recovered and Gregory was not as aggressive.
I can't see Perryman before middle second round and more likely the third.