I am working on the Allen family in Jackson Co., TN.Not sure if this will help, but it may give you a few leads to check.In the marriage records of Randolph Co., AR I found this: Thomas H Smith married Elizabeth Allen on 4 May 1862. Don't know what the H stood for, but who knows, it could be your Harve.Betty can certainly be a nickname for Elizabeth.
Zera T Allen married first to Nancy Price in Jackson Co., TN sometime before 1832.Sometime around 1848 they moved to Randolph Co., AR.Zera and Nancy did have a daughter named Elizabeth who was born in Jackson Co. about 1840.I don't know what happened to Elizabeth or who she married, but she was living in her parents household at the time of the 1860 census and not there at the time of the 1870 census.The time period is right for this Elizabeth listed as married to Thomas H Smith.I have not done anything much to follow this Elizabeth, but do have quite a bit of info on Zera T Allen and his descendants as well as his brother Solomon Allen and their sister Susan Allen.These three Allen siblings were in Jackson Co., TN by as early as 1830.Solomon and family as well as Susan and her family remained there with only Zera T leaving the area for greener pastures.Note the name Zeary for one of your Harve and Betty's children. Could be named for her father Zera, what do you think? Zera T and Nancy Allen also had a son named Daniel and a daughter named Margaret among others.
If you think I can help, please contact me at KRai3@aol.com.