Sorry I'm a bit late to this...real life
Anyway, I'd be very interested in anything you've got on George and Barbara's children.
I've got Rankins, Reids and Morisons at various points in my tree but nothing that jumps out and hits me as linking up directly with what's here, It is possible there's a link hiding in there somewhere...
Barbara Killah born 25th May 1800 to William Killah and Isobel Rankin. Siblings James 11th Feb 1798, William c.1802 and Mary c.1805
Isobel Rankin above born 11th March 1771 to William Rankin and Jean Morison
William Rankin above born 1748 to William Rankin and Anne Reid. Siblings (I've not checked any of these out!) Isabel 1760, Agnes 1745, James 1746, George 1755, John 1750, Alexander 3rd December 1762, Anne 1752 and Elizabeth 1755.