I ran across your message while searching for Sarah Guinn's family. I have some information I'd like to compare with yours, specifically about the Guinn family. I am descended from Malinda Gwin/Guinn on my mother's side. I think Malinda is a sister or cousin of Sarah, but I don't have any proof.
The Guinn and Ash families lived near my Holleman ancestors (my mother's side) in Tennessee in 1840.
In 1860 Hiram and Sarah (Guinn) Ash lived next door to my g-g-grandfather Wyatt and Eliza (Parker) Vaughn and family, and Hiram's son John and wife Sarah (Carmichael) Ash lived next door to my g-g-grandfather William A. and Malinda (Gwin/Guinn) Holleman.
I was also wondering about the ages you list for Hiram and Sarah. According to the 1850 and 1860 Rusk County, Texas census records, Hiram would have been born in 1813, and Sarah in 1812. The 1840 McNairy County, Tennessee census also indicates Hiram was born about 1813.
I'd like to send some excerpts from Rusk and Panola county cemetery records, and the census records I reference. If you will reply to me at my email address, I'll send those to you.
I hope this information is of some use to you, and I would be glad to exchage information. I'd particulary like to explore more the realtionship of the Ash and Guinn familes.
Some of my later Vaughn relatives married into the Gwin/Guinn family, specifically M. Cumile Gwin and Julia Frances Gwin, but I don't know who their father was.
(Julia Frances Gwin married first ? Feemster, then William Thomas Vaughn. M. Cumile Gwin first married Hyram W. Holleman, then William Thomas Vaughn after her sister Julia Frances died.)