Thanks, yes, I believe your line and my line are related. Recently I was looking at a copy of the book "Pioneers of Marshall County, KY: with Edwards, Hiett, Pace, Starks and allied families". That book has a good bit of information on the Marshall County Hiett's with sources.
According to that book both your line and mine trace back to a William Henry Hiett from SC who migrated to KY in 1825. My John Hiett and your Aaron Hiett are both sons of William Henry according to the book.
So thanks for the reply; it is good to be in contact.
My question stands if anyone can help us pick up the Hiett line in SC. I'm not sure what are the best sources of information for the late 1700's for the Greenville area.