Jim McNally doesn't call the plays or choose the blocking schemes. That is the offensive coordinator.
As far as our current personel, we have one WR capable of playing the 1/2 role and we don't even have an adequate #3 WR ot top Tight end. We have a center who gives the opposition a physical mismatch to exploit and a right tackle who is decent but not physical enough. Not to mention a QB who is in his first year as a starter.
If I am a DC against the Bills, I mix up a lot of coverages and blitz up the middle, shading to the right side most of the time. Stuff the run on early downs, and hammer Edwards on throwing downs. The Bills as they are currently constituted will not beat anyone by throwing on early downs- they are best off sticking with high percentage plays and managing downs and distances.
If their draft picks turn out to be upgrades, this can definitely change, but that remains to be seen