I assume the Dupree comment was not intended for me, but I'll address it anyway.
Some people think that a way to get one of the elite but undersized pass rushers onto the team would be to use him like Denver used Von Miller. VM plays SLB on base downs and moves to DE in obvious passing situations. He also blitzes from his SLB position in the base and at times they have the DE on the opposite side hold up his rush or drop into a shallow zone which gives them a 3-4 type look.
The Giants also moved Mathias Kiwanuka back and forth between SLB and DE over the years. He had 4.5 sacks in 10 games his 2nd year in the league while playing SLB.
Think of it as if you had a pass rushing specialist that comes in on obvious passing situations but instead of being on the bench on base downs, is on the field as the SLB.
Seattle does it to some extent with Bruce Irvin, but he does not line up as a DE nearly as often as Von Miller because Irvin plays WLB and stays on the field in passing situations as a Nickel LB. Irvin did have 6.5 sacks this season.and Von Miller had 14.
The Cowboys did try doing this to some extent with Kyle WIlber but he is obviously not an elite pass rusher.
I do think there would be some Pros and Cons to doing this. It would get an extra pass rusher on the field in the base and it would allow you to draft a guy that has elite quickness for pass rushing without having to have the size to hold up against the run as a DE. On the downside, if use a 1st round pick to get this player it's most likely because of his pass rushing ability while his ability as an off the line LB might not be 1st round worthy.
Having said the above, at 6-4, 267 there is no reason no reason that Dupree can't play all downs as a DE.