Smith is already starting at one of the DT spots, so someone else will have to step in for Keenan.
Reynaud at 265 is no where near big enough to play inside yet and even though Hill is certainly more DT than DE, he's not really at the ideal weight either. It would be a big stretch to have Collins or Overton slide in as well since they're sub 275 and are DE's not DTs. They could probably take some reps on passing downs, but if they are in on situations that could be either run or pass, if I was the opposing OC, I and saw any of those guys in as a DT, I'd formation us to ensure the WOLF was next to them, making that a really small side of the line and a and then I'd run right at them and go HUNH to prevent subs and do that until you stopped me or I scored. A 275# DT a 250-260# OLB wouldn't be much of a match for 2 310+ OL...
Beaman doesn't have a lot of reps, but got some time in the bowl game and looked good then and has good size. Behind him, there's potential, but no experience. Faga and Mboumoua are the other 3 down DT style guys we have, and I don't think either has any meaningful game time, then TF Simmons. We just don't have much experienced depth at the big boy spots.