It is great that you saw the post. My GG grandfather was George W. Martin is from the same line. My grandmother was Ada Martin Lemley.
It was only recently that I returned to researching the Martin connection, after getting bogged down in court records on the Lemley side of the family. From your list, I see that we are talking about the same ancestor. Through the years, I had been able to identify all of his children from the 3 wives, but never made much progress on who the daughters married.
It is likely that I have probably met a few descendants of James Arthur, as I am in North Alabama. My mom has told me a little about her Uncle Jim and Aunt Jettie. She has also mentioned a reunion in Alabama, but I do not know if she has attended or other details
Feel free to contact me at firstname.lastname@example.org