Re: Searching for John McLeod
I think that is wrong information by her widower. When there is a conflict between information on a marriage and information on the death certificate, I tend to believe the marriage because in that case the person is alive to provide the information, whereas with a death certificate the information is only as good as what the informant thinks he knows.
Be very careful not to make assumptions about Christian Munro and her husband. In the 1841 census adults' ages were rounded down to the nearest 5 years. The census was taken on 7 June 1841, so if Christian's stated age is accurate she would have been born between 8 June 1771 and 7 June 1776. Also, she said in the 1841 that she was not born in Moray. In 1851 Donald and Christian jr say they were born in Nigg, Ross and Cromarty and Rebecca was born in Nairn, and in 1861 both Christian jr and Rebecca say Nairn. There was quite a bit of migration from the northern counties, and a family starting out in Ross-shire, moving to Nairn and then moving again to Moray wouldn't be unusual.
Do we know what happened to Rebecca's siblings? She and her sister were both described in the 1861 census as 'retired farmer' (and so was the 7-year-old John!). Her brother could be the Donald Ross, aged 49, who died in Dyke in 1857. Christina Ross, mother's maiden surname Munro, died in Forres in 1861, aged 48. Their death certificates should settle that.
You also said, "On the birth record of John McLeod, in 1853, it says his mother Rebecca, was from Snab and his father was from Dalvey. And what does it mean when there is a blank for where he was baptised." It means that the clerk probably wrote it down after the event, and didn't have the exact date to hand, and then forgot to fill it in later.
There are several places called Dalvey, but the nearest one to Snab is this one https://www.geograph.org.uk/gridref/NJ0058 so it would be reasonable to suppose that John's father Donald McLeod lived at this Dalvey, in the same parish. This map shows both Snab of Moy and Dalvey House https://maps.nls.uk/geo/explore/#zoom=15&lat=57.61561&lon=-3.68723&layers=5&b=1 (you may need to zoom in a bit). But farm workers, especially young unmarried ones, did tend to move around quite a lot, so he may not have been there on the day of the 1851 census, let alone the 1861.