Although I have no documentation as proof, I believe William Tharp in the 1820 Lee County Census, with wife and sons, is the father of George and son of Polly in the 1820 census. George, wife and children are in 1850 Cass Co, MO, census. George's eldest son was named William, probably after George's father. In 1860 Kansas Territory, Lykins, George is listed next to Benjamin Tharp b abt 1794 VA. I believe Benjamin is George's uncle, brother of William, and son of Polly (with sons) in 1820 census. There are several of us researching this relationship so I'm hoping you may have found further information since you posted.