Just to add that you can now also search deaths between 1855 and 1880 using mother's maiden name as well on ScotlandsPeople. The deaths of women in Scotland are registered under both their maiden and married names, so once you have identified a potential candidate the trick is to search in that registration district using just their forename. Any individuals that you turn up with the same age and reference number, but with different surnames, will be the same woman, so if you know their maiden name this gives you a way of searching for potential marriages given that you now know their married surname.
The Scottish birth and marriage indexes on FamilySearch, which are free to access, also give you an avenue for finding the births of children from 1855 to 1874 by searching on their parent's names, and this will also return their birth dates as well. There is a corresponding index for marriages as well, I'm not sure of the exact period this one covers, but presumably at least the first 20 years of statutory registration. Both indexes also cover the pre-1855 OPRs, but searching on ScotlandsPeople gives you much the same information for the OPRs.
