Thomas J. Sanders, Dyer County, Tenn - Who are my parents?

I am researching my GG-grandfather (Thomas J. Sanders 1839-1916)  who was a Baptist Minister in Newburn, TN. I have found his certificate of death that lists his father as Tom Sanders born in Mississippi. His obit states that he was raised by his mother Susan but no other information is found on her. 

My last living uncle (Thomas J.'s grandson) has died now but he told me that his grandmother was a full-blooded American Indian. I have exhausted all other lines of ancestry except this one and would love to break through and find the parents of Thomas J. 

In many of the common online research venues, Thomas J and Thomas R (his son) are interchanged causing a slight mess. Since Thomas is such a common name in my ancestry, it can be difficult to figure out much of it. Thomas J. Married a few times and my mom tells me that they called him John. 

Wives:

Mary E. Thompson,Moore,Blessing,Richie  (1838-1910)

Candis M. Hall (1843-1873)

Possibly Mary Johnson as well  (1838- )

Any help at all to find the parents of Thomas J. Sanders would be greatly appreciated.