Rufus Holmes would be my GGG uncle. From family lore, and certainly without documentation, my understanding is the group was returning to Missouri and encountered Federal troops whom they fired upon. The group was chased to NE Arkansas where they were captured and shot on the spot. Family members of the 7 traveled to Arkansas to retrieve the bodies which were subsequently interred at Cowan Cemetery. I do not have any information on the living (if any) GGG grandchildren. However, there are numerous GGG and beyond nieces and nephews descendant from his brother Lewis Holmes. Let me know if I may be of any help in your endeavors.