I'd probably do something like:
LE/RE - 4-3 Balanced - You want some speed, but you need run stopping as well, especially on outside runs, so you don't want to weight totally to speed rushers. Top 3 Ratings I look for: ACC, PUR, BSH
DT - Nose Tackle - Big guys in the middle and wreak havoc on inside runs and make you more secure about spreading the d-line out for better edge protection. Also will help keep your gaps clean for the LBs. Top 3 Ratings I look for: STR, ACC.
LOLB - 3-4 Pass Rusher. With the SS on the strong (typically the defensive left) side, I like to let the LOLB be more aggressive. Even if I don't do much blitzing, someone who's fast with good acceleration can play that aggressive run-blitz role and cut the outside off before it gets going, helping the SS/LE out. Top 3 Ratings I look for: SPD, PUR, BSH
MLB - Run Stopper or Balanced. I want my MLBs able to do just about anything no worse than decent to slightly above average. He is the eraser that's on the pencil, the safe word that lets everyone else try to do too much and not get destroyed. I want to tell him to do anything and he'll be able to do it within reason. That said, the three things I think a MLB must have is tenacious battling through blocks and traffic, relentless pursuit, and getting his man to the ground first time every time. Run Stopper weights toward those three things, so you can see the guys that have a shot. Then you can "tie break" with the rest, based on how you want your LBs to play vs the pass, etc. Top 3 Ratings I look for: basically all of them - but if I had to pick 3, PUR, TAK, PRC
ROLB - Balanced. Unlike the LOLB, this guy has no help except maybe a FS that need to roam far to get involved in the run or a CB that may or may not be physical. So I don't want him going all-out at the QB or trying for big loss plays. I need him to read and stay free either for backside pursuit or stringing out the play. With the DE on the edge, the ROLB needs to know whether to attack inside or outside. He can't just pick one and go, leaving the HB free to go against him and possibly in the open. He also needs to be decent in zone coverage, at least for me. Top 3 Ratings I look for: PRC, BSH, PUR
CB - Man to Man. Since 46 is often an attacking defense on some level and there's usually only one safety in the usual pass defense positioning, the corners need to do more on their own in coverage. That said, depending on the flavor of 46 you want to run, there's a place for a Run Support CB that's at least decent in MCV, especially if he has good PRC as well. Top 3 ratings I look for: MCV, PRC, one of TAK, POW, STR, BSH.
FS - Playmaker. Quite simply, this archetype weights the three things I look for in a FS. PRC (I know what's coming), AWR (I know what to do about it), PUR (I'll get there no matter what). Considering he might have the whole field to deal with, the only other thing I'd tack on is SPD simply because he has to physically be able to cover the ground. In a 4-3 or 3-4, the PUR usually lets him run support when needed or to make a play. In the 46, the PUR lets him get involved more quickly if he sees a breakdown. Top 3 ratings I look for: SPD, PRC, AWR
SS - Balanced. Again, just what I'd look for in a 46 SS right on the type description: speed, agility, coverage, tackling. Enough said. If I had to give up one, I'd give up top speed. He's likely going to be covering TE's in man, and zone doesn't really need a ton of speed. Man needs agility to stay with cuts, coverage is self-explanatory, tackling is needed if he's to fill his "4th linebacker" role well.