Rolle is a physical cover, a field general & would be the best of the bunch blitzing off the corner to pressure/sack the QB, Dunta is not big enough so he would be the best compliment, however should be gone in the top 5 picks. Marlin is a true cover corner who plays tight to the reciever & solid tackler. Webster is alot like Dunta but without the explosivness. Justin Miller is actually the best corner after Rolle, has explosive speed like Dunta and much bigger at 200 lbs.
As far as DJ goes here is one scouting report from the huddle-