I know it's a long time since you posted your query but perhaps you are still involved and continuing the research? In any case, the small snippets of info I have here you may already have yourself by now! Apologies if so.
I am a great grandson of John, brother of your Alexander. Unfortunately I do not have any information further back than you have regarding the McRae side. John married a Whitgreave and there is much history on that side of the family going back to the 1100s, but that is probably only of incidental interest to you.
You mentioned that Alexander and John's father (also John) married Martha McRae "somewhere in the early 1820s". In fact they were married on Feb 6 1823. Marriage register records show that "John MacColl Glencamgarry and Martha McRae Murlaggan" were married on that date.
Also, John died on 8 Feb 1840 in Moror, about 40 Km west of Fort William, and he was buried in the Corpach cemetery (I have a photo of the grave headstone). It is unfortunate that I had not read your forum posting when I visited the cemetery as I did not realize that Martha was buried there also! I knew that she had spent her latter years in Ballachulish and the Letterfearn, dying, I thought, in Glenelg.
Like your Alexander, my great grandfather was also a school teacher and school principal, being associated with a number of schools in rural Victoria (Australia) from the mid 1770s until he died in 1892.
If you have any further info on Martha's background, I would be pleased to hear of it.
Reply posted by : Paul McColl