What is the best way to apply the drywall after I apply the styrofoam to the concrete basement walls? Do I put up 2x4's every 4 feet and then use vertical bracing to apply the drywall? Or is there a better way?
Is there a trick to prevent concrete nails from bending trying to attach 2x4s to the concrete?
Build a standard stud wall framing using 2x3's or 2x4's on 16 inch centers, just inside the styrofoam.
You could have also installed 2x2 furring strips directly on the concrete wall but you can't do that now because the styrofoam is already there. Also, for an exterior wall, 2x2's won't leave enough space for non-porous non-mold-attracting insulation of enough R value.
With the styrofoam in place against the concrete foundation, any kind of additional insulation can be put between the studs.
Tornado victims: Do not rush to rebuild. Take your time and look for and get a good contractor. Or consider selling the property and moving to a home that is ready to live in.