There is another Waters connection, besides Sarah Waters, the wife of Jacob Garrard. William Waters Garrard's mother was Martha Newsome Hardin, daughter of Mark Hardin, who was son of Martin Hardin and Lydia Waters. That Lydia was the daughter of Thomas Waters and Rosa Wickliff. That Thomas was the son of another Thomas, son of William Waters, son of Edward Waters and Grace O'Neill.
I still think William Waters Garrard was named for his great grandmother, Sarah Waters. However, who really knows?