Andrew, I didn't see your message until now. I believe the family you mention is the one I belong to, although some names differ. The Donald MacPherson you refer to, who was married to a MacVarish woman, was my ggg-grandfather. This family is documented in Mabou Pioneers (vols. 1-2). The author interviewed my grandfather Donald MacPherson for that publication. According to my grandfather, there were seven children in the first Donald's family, but only four of them are named: John, Angus, Donald, and Margaret.
I believe "Loch Enort" is Loch Eynort (sometimes also spelled Loch Einort, and sometimes spelled as one word). There are only two such named places in Scotland. One is on Skye, the other on South Uist, in the Outer Hebrides. The South Uist location is the most likely for this Catholic family, and there were MacPhersons living there at the time of emigration.
My MacPhersons settled at Black River, Inverness County, on Cape Breton Island, and I grew up near Sydney. My family is also listed in the DNA project notes recently sent to this list (Line 8). If we are talking about the same family, then you must be a cousin of mine. I'll be happy to hear from you and continue the discussion.