I think Carrigan is an absolute star in the making from what I've seen as well but he'd be going EXTREMELY well to have been able to produce what Fifita has already shown. From what I've seen so far, Fifita looks like the best of the lot comfortably.
Carrigan and Haas would be next in line followed by Su'A...and Su'A is a gun.
I doubt the Broncs hold on to Flegler but I think they will manage to hold on to Carrigan, even they end up moving on a McGuire, Glenn or Mago if need be. I wouldn't be surprised if TPJ ends up somewhere else eventually as well.