Redwine has intriguing potential, but I wouldn't expect much out of him this year.
Johnson I think will contribute, but ultimately I think he'll be like Tracy Howard - his lack of size and athleticism is going to limit him from ever being an impact player.
Quan's a better athlete. Already Tracy's size. He'll be doing damage at nickel and can play both in the box and as our center fielder. Howard was a very good player on a team that won states his sophomore year and lost it during his senior. Quan was one of the better playmakers in dade since his freshman year and on some bad teams.
You think Johnson is going to play nickel? You think he's got the athleticism to do that? I don't see it.
Why not? He's a playmaker with great change of direction, he's physical and can be effective doing multiple things (blitzing, inverting, etc..) Whether it's forcing fumbles or getting INT's, he's better off near the line of scrimmage where the majority of the plays occur. In a zone he'd have to run underneath a number 1 receiver, which almost anyone could do. In man coverage he's got excellent change of direction that will help him run with quicker slot receivers, while having help over the top.
His buddy Tim Irvin is already starting at NB for Auburn. Both players are basically the same, except Tim is a bit stronger, while Quan has better ball skills.