Hello, I know this is not really a new post, but it sounds like you and your cousin have a wealth of knowledge about MacKenzie's and I could use some help!
I have been able to trace my paternal line of MacKenzie from my father as far back as 1775, where is get to MacKenzie-7655, and then it's been rough sailing. Pun intended, because John McKenzie was a Shipmaster who seems to have died in 1822 in Jamica. Was it at sea? I don't know. I have records of his marriage which took place in Canada. His children were all born in Scotland. His wife is from England. I have traces of him in Scotland, and it seems he was born there but i have yet to find many records other than his will, recorded in Glasgow Sheriff Court Inventories and also an inventory from who I believe is his brother who's will gives him a ship called The Lady McKenzie which I can't find record of anywhere, I would love to go further with this line, and have leads to who his parents were but nothing definitive. Since my Grandfather the line has always had a John and an Archibald, which you would think would make things easy to find, on top of the tradition of the female daughters taking the maiden name of their fathers mother as a middle name, but it's not! I would REALLY love any help you might offer or any direction you might point me in!!!