How do I level a 2x4 on a concrete basement floor with an irregular surface?
If I'm interpreting correctly, your framing isn't so much structural as a place to hang drywall/ whatever. If this is the case, then a bunch of construction adhesive will do fine. If you can, add an "L" bracket or two to the wall to tie it all together. 

Pressure treated wood is probably what your AHJ would call for in this setting.