1. James Benson died in Mecklenburg Co abt 1779 "interstate" out of North Carolina, location is not listed. I suspect it is him but he would have been kicked out of the quaker religion for being a soldier. Margaret Kerr Benson remarried a Lambeth and is also listed in her 1805 mother's Rowan Co will. Their only child John Kerr Benson married Jenny Finch in Mecklenburg Co surviving quaker records date and had 2 daughters. One daughter, Malinda Benson, married a John Carrothers in Mecklenburg Co bond. Their descendants still live in Mecklenburg Co, NC area. Many are online.
Have you done the DNA test? I do think you're Marcus Benson line is the PA Quaker line. I'm trying to get more Benson surname folks to get tested as there are Benson's from MD/DE and elsewhere traveling through the area.