Did your Stillings information come from Blake Stillings of Alberta, Canada? I corresponded with him in the 1980's. He passed away in 1991. I also have his writings which are very good on the Stillings family.
My proof for Ellen Alabama Preston being the daughter of H. B. Farish is the marriage record on file in Wilcox County. It states that Thomas P. Preston married Ellen Alabama Farish on October 14, 1852 in Wilcox County, Alabama. Also the estate settlement of Hazelwood Buckner Farish lists one of his daughters as Mrs. E. A. Preston. The 1850 Census of Wilcox has Ellen A.. age 13, with the family of H. B. Farish.
Ellen was only 14 when she married Thomas P. Preston. Thomas Preston died in the civil war. Alice, age 6, is listed as a daughter on his estate settlement.
There is also a dispute about the father of Levinia Farish who married William T. Stillings. The name J. D. Farish was such a common one is probably the reason. There is a marriage record, never used, in Wilcox County that lists Mary Jane Stillings in a marriage to John D. Farish. Mary Jane was the daughter of Levinia and William T. Stillings. I have reliable information that they moved to Texas to marry. After his death, Mary Jane married Sam Harris and has descendants.