Two useful sites are Libindx, which allows you to search for people from the Nairn/Moray area, and FreeCEN, which gives transcriptions of some censuses. Using these and FamilySearch, I have come up with the following:
The Libindx site gives the death of your John Urquhart in 1892. His age is given as 92.
FreeCEN shows the family at Cuthbertown of Delnies in the 1851 census -
John Urquhart, 47, born Alness, Ross and Cromarty, ag. lab.
"Amelia", 45, born Kiltearn, Ross and Cromarty
Mary, 24, born Kiltearn
Alexander, 7, born Nairn,
Agnes,5, born Nairn,
John, 4, born Nairn.
Since we now have a birthplace for John, FamilySearch shows a John Urquhart baptised 10-1-1801 in Alness to Alexander Urquhart and his wife, "Girsel Boid".
Girsel or Grisel are older Scottish forms of Grace, as Aemilia, Amelia, Emily etc. are alternatives.
FamilySearch shows a marriage for Alexander Urquhart and "Grace Boyd" at Alness on 21-11-1789. This may be the date the couple were "booked", rather than the day of marriage itself.
You should see the entries on the ScotlandsPeople site. It is the official pay to view site run by the government and allows to see the actual entries, not transcriptions. It is not so very expensive if you know exact details, as the ones above. The actual entries will perhaps give exact addresses, witnesses to baptisms etc.