I don't know of any relationship between Horatio B. Warbington, Sr. and Benjamin Merritt.
Horatio B. Warbington, Sr. was a merchants of sorts; at one time maintaining a "storehouse" for his wares on lot number sixteen in the now extinct town of Old Marion, Lauderdale County, Mississippi. He was also very active in buying and selling town lots during 1838-1840.
Horatio served on the board of trustees for the Marion Academy, after its formation in 1837. Also, he was serving as an "acting Justice of Peace" on August 1, 1838. Perhaps Horatio's home was one of those described in the Paulding Eastern Clarion in the year of 1837 as being among the "handsome family residences" of old Marion.
Following the marriage of his only child, Nancy Ann, a bitter court battle raged from October 25, 1839 through November 28, 1840 between Horatio and his estranged wife, Margaret. Prior to being granted his divorce decree (which was secured by his attorney in his absence), Horatio had sold his properties and left the state, moving to Fayette County, Alabama.