I might be able to help you with your Cynthia Ellen Rigsby.
There was a Cynthia Rigsby born about 1862 in Lawrence or Johnson Co KY. These are neighboring counties, and Blaine is in Lawrence Co. A group of Rigsbys had been in Lawrence Co since 1830, and some of them moved to Johnson Co between 1860 and 1870. Cynthia is in Johnson Co in 1870 and 1880, and apparently married before 1900.
She was the only Cynthia among those Rigsbys, and there seems to have not been an Ellen. Does 1862 sound like a reasonable birth date for your Cynthia, and was she married after 1880? If so, I can give you her line for a few generations back.