Keep in mind as you research in NC that the county lines kept changing and the same location might have been in 3 or more named counties over the years,..particularly Western NC.
Your Keener connections do have some Cherokee Indians marriages before the Cherokee were moved to Oklahoma Territory...sometimes openly married, other times Indian blood not know. I can imagine most family in this area have those same things happened.
For your best bet on Civil war records.. go to www.FOLD3.com
I have found many of the Keeners there.
I do have abt 2 dz Donaldson connections in western NC and North GA..but not tied together since I don't have a direct link here.