Re: John Mackay Problem ..............
Looks like Hiltown to me. Definitely not an M at the beginning of it.
I see a Hilton between Redcastle and Muir of Ord https://www.geograph.org.uk/gridref/NH5449 and https://maps.nls.uk/geo/explore/#zoom=15&lat=57.51272&lon=-4.42572&layers=5&b=1 which is in the parish of Urray. This would fit with the baptism record but not obviously with John saying he was born at Redcastle.
Though I see from the 1855 valuation roll that Colonel Baillie who was the proprietor of Redcastle was also the proprietor of Tarradale, which is in the parish of Urray immediately next to Redcastle which is in the parish of Killearnan. Hilton is part of the estate of Tarradale.