I'm unable to find the parents of George Sharp. Census records indicate that he was born in Virginia. In 1799, he was considered an orphan in Caswell County, North Carolina. At that time "orphan" doesn't necessarily mean that his parents were dead...it could mean that his parents were unable to care for him and placed him for adoption. His brother Eli was also placed for adoption at that time.
Mary Hamilton was married to George Sharp in North Caroilina. In the marriage record, she was named Polly Hambleton. Polly is a commone nickname for Mary and Hambleton is a spelling variation of Hamilton.
Looking for the parents of George Stewart in Northern Ireland.
She was married to George Stewart. I can find no evidence of her in Northern Ireland.