I've been told there were three Andrews there at the time. "My" Andrew appears to have have been married to Florence Henderson.
. Andrew Russell Sr: Born Northern Ireland 1716. Died Va 20 Nov 1780. Father of 4. Son of 16 & 17.
9. Florence Henderson: Born Dumfermline, Fife, Scotland, British Isles 1718. Died Fishersville, Va aft 20 Jul 1764. Mother of 4.
Don't know if this helps or just confuses more but as near as I can tell, this Andrew's parents were Adam Russell and Isobella Millar. My facts are getting "iffy" here though.