I believe William Rice, was a son of John & Letisha Rice, and is the same man as the son-in-law of Henry Williams although the evidence is circumstantial. See his relinquishment in name of his wife Nancy - see below. There is also deed evidence a William Rice lived near Henry Williams.
William Rice was appointed executor of Henry Williams' estate along with son Daniel Williams when he reaches age 21, and Henry's wife Elizabeth in 1786. Most of the bequests are brought up to the value of Nancy Rice - I would assume she is the eldest child and she had received a slave, based on the other bequests.
12 Mar 1804. William Rice relinquished interest in land warrant #1759; his interest due to former wife Nancy being heir of Henry Williams.
Nancy WILLIAMS and William RICE were married before 1785.17 William RICE17,37,38, son of John RICE and Letisha ESTES, was born in 1753 in Hanover County, Virginia. He died in 1831 at the age of 78 in Wilson County, Tennessee.
William is said to have married 2nd to Esther Chounan, 21 Dec 1793, in Caswell. Before 1810, they moved to Wilson Co, TN. He is said to have died 1831 at age 78.