By 1865, my line had been in Alabama for at least 35-40 years. I do Know that my ggg-grandfather, Craven Harris had at least 4 brothers, Thomas, George Jr., William and Micajah, all of whom were born in South Carolina. Craven's grandfather, Burr Calvert Harris (III), migrated from Prince William county Virginia in late 1772. He bought some land in Newberry District in January of 1773. Burr had at least 5 sons, Burr (IV), George, Thomas, Obediah, and Micajah.
I have no proof that any of them owned any slaves but I also can't prove they didn't.
I have a tentative track that Craven's brother Thomas also moved to Alabama around 1820 but that does leave a lot not accounted for. Of course, this wasn't the only Harris line in the area. You have a major job tracking that root. I wish you luck and good hunting.