IMO, in a perfect world, Dallas would draft a Hybrid LB/DE like JWalker, as well as add a 3T (Nolen or DWalker) and a 1T/NT like Grant, and then go get a Mike (Knight or Barton or even JCampbell)
1 -- trade down pick up a extra lower 3rd and then still get JWalker
2 - Nolen won't drop but it would be nice here -- there are several 3T options.
3a - DWalker (maybe a 3T if he doesn't learn to anchor and shed) or Grant ----would either of these fall to 76?
3b - DKnight or LBarton or if by some crazy happening JCampbell fell this far.....really needs instincts (smarts), strength, attitude, size and speed here.
You would have defense with JRogers, DWalker, Nolen, Mazi that would be a good inside DL
If you resigned Gholston and CLawson, you would have Gholston, Kneeland, SWilliams, and CLawson to play the DE/5T
JWalker and Parsons are Hybrids and could go DE or Mike/Sam for that matter and play massive roles.
As long as you still have Overshown/Liufau/Clark to play the Will and some Sam. Knight or Barton at Mike.
If Overshown were healthy, he could easily go to a hybrid LB/SS with Wilson playing SS/LB, on passes one would be short outside zone, and the other usually strong side seam.
Mlb would need to stop the run by stacking and shedding, and be able to drop into middle zone on passes.
The base most people try to play till playoff time is a nickel. Weakness of the nickel is rushing. OC will run all day on a nickel D, forcing you to bring up to the box one or more defenders.
With what I am suggesting, you could run a 3-4 with JRogers at NT, Mazi and DWalker at T, and use Parsons/JWalker as the OLB.
Maybe they would rather have a 4-3 with Kneeland, Nolen, Mazi, and Gholston, and use Parsons/JWalker as the Mike and Sam.
Maybe if Overshown was healthy, JWalker/Parsonsas the Mike/Sam, Overshown as Will/SS, Wilson at SS/Will, SWilliams at one DE, CLawson at the other, Nolen and DWalker in the middle. Cover 3 with Bland and Diggs deep, and a deep FS. Speed and strength.
I could see lots of fun designing and building defenses, depending on the offense strengths, for the DC. Need more pressure or gone to nickel.....maybe Parsons and JWalker at DE , and Nolen and DWalker inside. Knight/Barton dropping to middle zone. Liafau, Overshown cleaning up at LB or even with Liafau blitzing.
If Dallas is smart enough to trade down and pick up an extra 3 (and the draft actually fall in their favor), and use FA to get a #2 legit WR like Diggs, Cooper, Kupp, etc.......and can figure out this RB issue........they could be very good next year.
The entire rest of the draft could easily go to picking high ceiling developmental guys (boom or bust) like OL, QB, RB, more DBs.
Summary: Sign a big name FA WR, figure out your RB situation (whether FA or 5th or can you get a higher pick for the one you want), and then draft a hybrid, mike, 3T, and 1T in the top 4 rounds. Rest of draft is for developmental guys.