I couldn't download the letter at that point (which I have now)

& I can see by how it was written I misunderstood although I did wonder about (what I thought were ages)

Apologies on the references which are from
www.scotlandspeople.gov.uk (Scottish Government site) which holds
all Scottish Certificates of BMDs etc. & is pay-per-view by credits (not expensive) although FREE to join & FREE Index to search.
There are many FREE sites for transcriptions of Census Records, BMDs etc. but the originals of
all Scottish Certs. can only be purchased at above site.
What were the names of Donald's children in order as this can be helpful if the naming pattern was used?
Possible Baptisms, no mother recorded on index i.e. there's a possibility of no mother's name on the actual register;
MACKENZIE WILLIAM
JOHN MACKENZIE
12 DECEMBER 1800 NIGG ASSOCIATE ROSS AND CROMARTY
MACKENZIE CATHRINE
JOHN MACKENZIE 19 SEPTEMBER 1802 NIGG ASSOCIATE ROSS AND CROMARTY
MACKENZIE ALEXANDER
ROBERT MACKENZIE
12 JUNE 1812
1812 NIGG ASSOCIATE ROSS AND CROMARTY
The only deaths I could find for a Lil (name beginning with) in areas mentioned were;
1883
MCKENZIE LILY 84 Nigg (Ross and Cromarty)
078/ 3MACLEOD LILY 84 Nigg (Ross and Cromarty)
078/ 31879
MCKENZIE LILY 80 Tain
082/ 5MCCULLOCH LILY 80 Tain
082/ 5Matching details for
Ref. No. would signify married i.e. can be discounted.
Possible deaths with family name which isn't common but hard to tell not knowing who parents were, mothers maiden name or when parents married/died;
1908 MACKENZIE ROBERT 74 (c1834) Nigg (Ross and Cromarty) 078/ 12
1934 MACKENZIE ROBERT 77 (c1857) Nigg (Ross and Cromarty) 078/ 9
1928 MACKENZIE ROBERT 69 (c1859) Nigg (Ross and Cromarty) 078/ 5
The deaths for a William in Tain don't match very closely with his age of 88 (c1787) yrs given in 1875 which was the reason I hadn't posted earlier (as with the ones for 'Lil' but for ref);
1878 MCKENZIE WILLIAM 100 (c1778) 082/ 18 Tain
1878 MCKENZIE WILLIAM 84 (c1794) 082/ 62 Tain
1885 MCKENZIE WILLIAM 85 (c1800) 082/ 32 Tain
Annie