Without an understanding of the job, it sounds like you are limited to sheeting the entire area, toeing in the sheeting enough below subgrade for a water cutoff. It also seems as if you will need to interally brace the sheeting against each other, as opposed to using a whaler tie back system...
In my experience, it seems like a number of states are finding a middle ground between epoxy coated bar and black bar, with superstructure concrete utilizing epoxy rebar and all substructure concrete utilizing black or plain rebar.
