The earliest appearance of the name COSTIN in New Hanover County records is on the roster of Captain John Ashe's Company roster in 1748. Among those listed are John, Peter and Stephen COSTEN.
Feel free to connect to my family tree to get Stephen Coston's line.
We have traced it back to John Costen, of East Farleigh, Kent, England in 1585
http://trees.ancestry.com/tree/46403556/person/6573524741