Thank you, Joseph, for posting the results of your careful and detailed research. We need both documented paper trails and genetic evidence to sort out the early American Boxes.
The few Box DNA tests we have show all those tested are related and all had ancestors in the Laurens, SC area about the same time.
Family records I have seen indicate most of the Boxes came from locations north of South Carolina. There is a record of a Will Box arriving in Savannah with the Oglethorpe colony in 1733. He died shortly after he landed, leaving a wife and two small sons. As far as I know, none of his descendants have yDNA tests.
Thanks again for sharing your good work. I hope we can get more Box males to share DNA tests to help us interpret what you are finding.