Hi Brian. I can't remember whether we've corresponded before, but I just wanted to mention to you and others that several of the surnames you mentioned are names from the early years of Argenteuil County in Quebec Province !
My ancestors were part of a KERR / HENDERSON family-group which left Ireland in 1823 and settled in Argenteuil County. They settled in "the former township of Gore" before moving to nearby areas in later years. And, there is a List for this township where more information can be found !
KERR's settled in several areas in Quebec Province, and we think some who settled in Compton County are somehow related to the ones in Argenteuil. There was a Dawson KERR who initially settled nearer NS or NB and then moved to Ontario Province, who we think was also related.
Betty (near Lowell, MA)