In my area they are a common native, but grow best in half day shade. Knowing how hot the Mobile area can get in the summer along with how intense the sun is in midsummer, I would hesitate to put them in the sun. The pH sounds similar to mine, but my soil is well-drained. Since there isn't any clay in my area, I don't know how clay tolerant they are.

If I were in your area, I would plant crepe myrtle, which is a lovely small tree when not chopped back and ends up about the same size I think. (but that might just be zonal envy on my part.)

No offense but I hate crepe myrtles.

I think you are right about the sun/shade part.