I didn't find any Christina McKenzie on 1881 census with Ann and Jane.
1871 census Drainie, part of Lossiemouth, Moray County
Alexander, 19, son, b Drainie, copper [apprentice]
Ann, 58, wife, b Rosemarkie, Ross-Shire
Ann, 33, daughter, general servant, b Drainie
Donald, 61, head, b Killean, Ross-Shire, laborer [out of employ]
Elizabeth, 8, grandchild, b Contin, Ross-Shire
Christina Donaldson, 5, grandchild, Drainie
Is this the Christina that you refer to?
This family fits with the one I found on 1881 census Drainie minus Christina and Donald. He likely is dead.
On 1861 census Inverness, there is a Christina McKenzie, with parents Donald and Ann.This is likely Ann's sister. No Ann.
I couldn't find an Ann b Drainie on 1861 census but here is a possibility.
Ann McKenzie, dairymaid, 21, b about 1840,Elgin Morayshire.
Here they are again.
1891 census Drainie No 3 Quarry Court [same address]
Ann MacKenzie, 79, head,
Ann MacKenzie, 50, dau, general worker
Jane MacKenzie,16, granddaughter, b Drainie
George Findlay, 19, lodger
James Eddison, 16, lodger
No Christina or Elizabeth.
I don't know how much you have. I just keep looking.
Christina McKenzie, b 30 Jun 1865, Drainie, Moray, mother: Ann McKenzie
Eliza McKenzie, b 20 Jan 1862, Kilmorack, Inverness, mother: Ann McKenzie
I couldn't find a marriage for any of them. IGI doens't normally have deaths.
1901 census has a Christina Farquhar, 35, salmon fisher's wife, 9 Elgin Road, born and living in Drainie. I looked on IGI for a marriage, christening of children but no luck.
Try this site: http://www.scotlandspeople.gov.uk/http://www.scotlandspeople.gov.uk/
It is a pay site but you should be able to findsome marriges and deaths for the McKenzies.