I listened to the complete interview and felt is was very informative.
One key thing is that in playing a 4-2-5 they don't need as many linebackers. But they will use all the LBs they have that earn snaps somewhere, special teams, on the line a la Amani Jones, maybe even at the Cash position.
LBs are typically 6'2"-6'3", 220-230 lbs. If they've got any speed at all they could do a lot of things.
Wallace mentioned they are cross training at the different positions and that's a good thing.
It feels like Phil Parker is setting the D up to be a more unpredictable, attacking D, I like that.