I expect Dremont Jones to be used very similarly to how they used Bennett. In other words, DE for running downs or DT for passing downs, but not necessarily every time that the situation occurs. Enough to become unpredictable.
Carter would be at DT every down. I believe his highest ceiling would be the equivalent of Grady Jarrett of the Falcons. If he reaches that level of play he would be well worth the #5 overall pick. You get a Jarrett level player on a rookie deal and you are well on your way to contender status. Add that to Nwosu, Bush, Wagner, and Jones playing to expectations and that front seven isn't really "years away" anymore. Depending on how quickly they mesh, they could easily be envisioned as an immediate force.
What this team really, really needs is a Chris Carson clone to help keep the defense off of the field as well as open up the deep ball via play action due to a well respected ground game. The further away from the goal line, the more you use K9. The closer to the goal line, the more you use the new bruiser RB. Hence, if K9 busts loose on your side of the 50-yard line he is trucking down the field for big chunks or taking it the distance. A single twenty-yard K9 run changes field position and consistently winning the field position battle will strategically put Seattle's splendid kicking game into play. Otherwise, once past midfield, you are methodically moving the chains with the bruiser RB. This is where Seattle's vaunted "three tight end" set comes into play. They really need that second back. More than just about anything after DT is addressed.