Wes, This can be rather confusing because Arthur Forbis (Forbes) the militia captain killed at the battle of Guilford Courthousewas married to Elizabeth Wiley, dtr of William Wiley and Elizabeth Ferguson. According to my info, their children were John, Arthur, Ann, Elizabeth, Mary and Martha. Son Arthur married an Elizabeth Matthews (ref. Guilford Co. Marriage Bonds). On 18 Sep 1786 son John Forbis married Elizabeth Wiley, who was the dtr of Thomas Wiley (ca 1756-ca 1812). I don't know anything about this Thomas Wiley's wife. This Thomas probably was a son of William Wiley and Elizabeth Ferguson (sound familiar?) Note that this early William had two wives: Elizabeth Ferguson and Mary Mebane. It is unclear which wife was the mother of any of William's children.
Confusing though it may be, I hope it is some help to your search.