Pedigreewise, these two should be the starters, but it's a tough jump for a rookie no matter when he was drafted. However, if both play like first-round picks, then this defensive line could make some noise. (Yes, I know that Lawrence was taken early in the second.)
I would expect, especially with Irving out, for Crawford to end up starting at LDE with hopefully Irving and Charlton eventually pushing Crawford back inside to 3-tech to team with Collins. Tapper and Moore could also have an effect on LDE, or at least allow Crawford to rotate some at 3-tech during Irving's suspension. Crawford, Collins and Irving are our best 3-techs (not necessarily in that order), so it would be best for the team if Charlton, Tapper and Moore could make it unnecessary for Crawford to play LDE.
I had thought going into the camp that Lawrence would end up at LDE and Charlton, Tapper, Mayowa and possibly Moore would rotate at RDE, but it looks like so far that Dallas intends to keep Lawrence at RDE.