I don't believe anyone can justify those assumptions at this point. Players arrive with varying physical development and at different fundamental development levels. It will be a year or two before we have seen enough of the young DTs to have an idea of what the ceiling is for each of young DT's. Unless one just explodes onto the scene this season, which could happen. But we haven't even seen some these young DT's play.
Gilliam had an easier time getting to 300+ lbs and has impressed the coaches with his early practice and limited play such that they believe he is the 3rd DT at this point. I believe that's about all we know so far.
Andrews offer list was spectacular. UM, OSU, Oaklahoma, ND, Miami. But some of those offers were reportedly based on him playing OL. It was reported that he initially had trouble at PSU putting on the amount of good weight he needed to play DT.
Cook reportedly had offers from Bama, USC and Oaklahoma.
Wafle ended up at Michigan while also having offers from ND, Oklahoma, MSU and others, but not from PSU.
I'm looking for at least a couple of the 4 to form a good part of the PSU DT nucleus for the next few years as PSU will lose Durant and Ford after this season.