We are searching the same line. I, too believe that Gray is the father of R.C. Felts.
I know that John West Felts death cert. shows father born in Va.
I am almost positive that R.C. Is for Robert Clement (Clemmens) Felts.
Gray''s wife (Rebecca Magee) had a brother with some part of his name being Clement (Clemmens).
There is mention of Gray Felts' will and Micajah was the adm. It seems he died before will closed and Robert took on some of the duties. Gray's will is in the Library of William an Mary (in Va, ?). I contacted them to get a copy, but they said too fragile to copy. The only way is to visit and take non-flash photos of it.
I am going on memory of some of these events right now, but some traces of connection between Gray, Micajah, and Robert can be found online.
I believe if we could get our hands on Gray's will it might mention R.C. In Tennessee or make mention of something that would let us know if this is the correct line.