Just a few helpful hints - St Joseph's District was probably 99% Catholic with only a few Presbyterian families along the borders. Angus and Jane lived amongst some Irish Catholic families between the Keppoch Mountain and Lochaber Lake. This area was close to and overlaping the Pictou and Guysborough County borders and often referred to as "Little Ireland". Most likely any kind of Church records would be found in Lochaber area Protestant churches and cemeteries. There were Cameron families down into Guysborough County. Being Presbyterian you will likely find Colin MacDonald's family in a similar area. I would look as far south as at least Sherbrooke for family connections. The 1871 census places a son, Angus as head of the household who is unmarried at age 30.
Hope this is of some help.
Marleen