Sarah Croft, wife of Richard Wigg, could not have been born in 1702 as she was married by 1705 to Richard Wigg.According to a book, "The Wigg Family" (edited by Lewis Kirby), on pg. 64 it states: "...by 1711 John Croft was a long enough established settler in South Carolina to be the recipient of a grant of 500 acres of land.His daughter Sarah had then been married to Richard Wigg for six years, and it is probable that both these men were already there in 1705, having come in during the preceding few years."
The section entitled "The Croft Connection" (pgs. 63-65) explains how the Croft and Childermas families are connected to the Wiggs as well establishing the Croft connection to landed families in England.
By this account, there is little doubt that Sarah Croft was indeed the mother of Edward Wigg - our ancestor.I hope this helps your research.If I can be of any further help, just ask.Pamela Rhett Molzan