"Guess" I was right.
On the first Research & Notes page, I had a note where I had wondered if Sarah Thaxton's sister, Phebe C., was Blufford's first wife.
I had no real reason to make this connection...it was just a wild guess after seeing some other connections, like Blufford's brother, Merrill, being married to Sarah Thaxton, who was the Aunt of Blufford's second wife, Sylvie Thaxton. And Sylvie Thaxton's first husband was the son of Merrill and Sarah.
Last week I received an email from someone researching Blufford's daughter, Ida Mason Turley. He said he had her death certificate which stated her parents were named Blufford Mason and Caroline Thaxton.
So, there you go. Blufford's first wife was Phebe Caroline Thaxton, daughter of Bannister and Phoebe Thaxton.