I believe the proof you need to conect Myrtle Rhoda Thompson Watkins to the family of Rodden Thompson exists.
There is a court document that list all of the heirs of Rodden Thompson.In this particular document in mentions Rhoda and her chilren.Here is a paragraph out of the document:
"That the said Rodney Thompson at his death left surviving him as his sole heirs at law the following to-wit, P. Thompson the plaintiff herein, Arch Thompson, John Thompson, L.L. Thompson, Thurman Thompson, Sarah J. Stinson (who was formally Sarah J Thompson), William Maloy and John Maloy and Polly Ann Renfro (formally Polly Ann Maloy), children of Nancy A. Maloy deceased (who was formally Nancy A. Thompson) and Rhoda Watkins (formally Rhoda Thompson) who is now deceased and who left surviving her Myrtle Watkins and James A. Watkins, her only heirs at law, Milly J. Maloy (formally Milly J. Thompson) and Dosie O. Grissom (formally Dosie O. Thompson).That since the death of Rodden Thompson, Polly Ann Renfro departed this life leaving surviving her Lula, Sarah, Bertha, James and George N. Renfro, her children and only heirs at law...That since the death of the said Rodden Thompson, the plaintiff, P. Thompson has purchased all the rights, title, claim and interest that the following named heirs had in and to the lands described aforesaid in this decree to-wit, Arch Thompson, Thurman Thompson, D.L. Thompson, Sarah J. Stinson, Elizabeth Buck, M.J. Maloy and D.O. Grissom, all of whom were children and full heirs to the said Rodden Thompson, deceased and also the interests of John Maloy, who owned one third of the share of one full heir and the court finds from the evidence addressed that the plaintiff counting the interest he owns in said land by heirship himself and by purchase is now the owner of eight and one third shares out of the twelve full shares in said land formally owned by all the heirs of Rodden Thompson after his decease."
I am a descendant of Thurman Thompson.
I can send you a copy of a transcription of the document if you would like.