My pick would be Green from Arkansas. Right now he's projected as a 3rd or 4th rounder, but I think he could skyrocket after the combine.
Beck has gone from being drastically overrated, to being drastically underrated IMO. I think he's a great backup option, who could exceed his projected draft position.
Chambliss is interesting, but he'll rival Kyler Murray for the smallest quarterback in football. If Tua, at 6-1, says he struggled to see over the line, you'd have to move Chambliss around, have him setup a little deeper etc.