Suzie, does Donald's marriage certificate say whether his parents were deceased?
Marshallina (I presume if it says Marshallima that the m is a mistake) is interesting, because there is no record anywhere on SP of a Marshallina or Marshallima before 1900. I am wondering if it is perhaps an east-coast Registrar's misunderstanding of the Gaelic given name Marsaili. This name is a derivative of Margaret and is sometimes anglicised as Marcella and sometimes Marjorie/Margery.
I think it would be quite difficult to mishear Christina as Marshallina!
I see that in 1881 the family were at 'Cement Building, Gamrie' **
Donald McLeod, 42, fisherman, born Tarbert, Inverness-shire
Margaret McLeod, wife, 42, born Gamrie
Donald, son, 11, born Gamrie
John Nicol, son, 9, born Gamrie
William Alexander, son, 7, born Gamrie
(I wonder why they didn't name a son Murdoch?)
Tarbert, Inverness-shire, is in the parish of Harris, as is the island of Pabba(y)/Pabaigh in the Sound of Harris. However Pabbay is about as far as you can get from Tarbert and still be in the parish of Harris.
**The LDS transcription of the 1881 census omits the useful information on the page headers of the original, including the name of the town or village, but it is in Enumeration District 1 along with Seatown, Bankhead, Burnside, High Street, Strait Path, Chapelton, Bog House and Harbour Head, so I think it is in Gardenstown. There is another Strait Path, in the burgh of Banff, which comes up in online searches, but it is not this one because the one in Banff is in the parish of Banff, and this one is in the parish of Gamrie. A look at the original of the census on SP would sort that out.
See also
https://canmore.org.uk/site/160640/gardenstown-cement-house-centre-house-and-store