Colvill's parentage seems to be a matter of great debate.Some say it was John (or John Joseph) Abercrombie and Ann Kellett (or Sarah Mitchell), and others say it was James Abercrombie and Hannah Pickard or Katherine Thomson or Elizabeth Sherrill.
I have seen a listing in an Etowah County, Alabama Heritage book that mentioned a James Gordon who emigrated from Scotland and married a "Miss Thompson" in 1732.It goes on to talk about their son John and his son William.At one point, it says that William moved with "his uncle" Colville Abercrombie to Georgia in the early 1800's.That would tend to indicate that John and Colvill were brothers and not father and son.I think it is probable that Colvill was the son of James Abercrombie and a 2nd wife (Hannah Pickard or Elizabeth Sherrill).There is no way to prove it at this time.
It mentions 3 Abercrombie brothers, William, John, and James, youngest of at least 10 sons of Sir James Abercromby (Baronet of Birkenbog) and Mary Gordon.These three presumably emigrated to North or South Carolina and were the progenitors of the Southern Abercrombie families.
A timeline in the same website talks about a Margaret Colvill, wife of Alexander Abercrombie of Brunston.Alexander of Brunston was working for Henrietta Duchess of Gordon in 1735, around the same time that James Abercrombie (son of Sir James) was a tutor to her son Cosmo, the young 3rd Duke of Gordon.This might provide a link between James (son of Sir James) and our Colvill since it is reasonable to assume that he may have been named for his aunt(?), Margaret Colvill Abercrombie.
Check out the website.Although it doesn't really draw any conclusions about Colvill's parents, it does provide some interesting data about the South Carolina Abercrombies.