I hope I am not leading you on a wild goose chase, but please just discard the information if it doesn't fit. Going back to the Clanbrassil, it may have just been the address in Dublin, I think there was Clanbrassil House or whatever in Molesworth Street, near my Foster/Forster and near the famous Letitia Pilkington.
I found the chart of the Adair and the Maxwell whom I thought may perhaps be associated with your family (I thought perhaps they may have been also connected with the Maxwell/Clanbrassil).
This may or may not be correct - James Adair, brother of Patrick Adair, minister of Carrickfergus m. Isabella, dau. of Robert Adair & Rachel Forbes.
James Adair was known as James of Belfast who was infeft of Corgie 1724.He married Jane of Glasgow. Children were: William Adair d. 1746. Patrick Adair d. 1764 married Jane or Anne dau of Joseph Touchet. James Adair the 3rd son resided in London, married Margaret Maxwell, dau. of Henry Maxwell.This James Adair was known as "James, the father of the Recorder of London." James Adair and Margaret Maxwell had a famous son, James Adair "Sergeant at Law" who married Elizabeth Spencer. It is only a very,very slim longshot that "Clanbrassil" may be your connection. However, I feel that Belfast also may be a connection there. Maybe your Jesse went to a Maxwell relation at Clanbrassil in Dublin for advice ?