I think Poz and Mitchell could play ILB.
I think Stroud would be an end in a 3-4. I think Kyle Williams could play nose. Not all nose tackles in 3-4's have to be 350 lbs (remember Jeff Wright). Probably not the long term ideal though.
Schobel though isn't really an easy fit - it would be kind of dumb to make him try and learn to play rush linebacker when he's our most effective lineman but, it would be kind of dumb to leave him as an end in 3-4 since it would neutralize his strengths.
without adding anyone new here would be my 3-4 defense next year:
line - Spencer Johnson or Kelsay, Williams, Stroud
LBers - Schobel, Poz, Mitchel, Harris with Maybin subbing in on the edges situationally