Hi Helen If your talking about Lewis and Mary Lockett Aiken's children, and I'm assuming they were twins (Betsy and Sally--b. 1757) try John Akin/Aiken (b. 1696--d. ? in Chesterfield Co. VA) and Katherine (b. 1698) (don't have last name on her yet).
John's father was James Jr. (married a Mary).His father--James Sr. (married a Sarah). Can help on dates for these also--if interested.