Still here, and welcome to RootsChat.
I do have quite a lot of information about Marjory, sent to me privately by others who have posted in this thread.
Marjorie Moug was the illegitimate daughter of Margaret Marjory Durnin, widow of David Moug (spellings vary). So she is not a blood relation of my Moug family.
She married James MacDonald in 1951.
However on James' death certificate she is named as Marjory Douglas, and there are eight births of children to James MacDonald and Marjory Douglas between 1928 and 1950. On all but the first one the parents say they were married on 2 January 1925 in Fremantle, Western Australia. There is no matching marriage in the marriage index for Western Australia.
I speculate that Marjory Margaret Mugg/Moug and Marjory Douglas are one and the same; that her father's name was possibly Douglas; and that for some reason James and she could not marry (perhaps he was already married) so they invented a fictional marriage in a place so distant that it would be unlikely that anyone would try to enquire about it. I noted that the birth certificate of their eldest, born in 1928, suggests that they were not married, because it was signed by both James and Marjory.
As far as I know Marjory's mother Margaret Marjory Durnin/Durno/Durhan/Durnie etc was born and lived her whole life in Kincardineshire. I don't think she could have gone to live in Fife between 1905, when her youngest son by her husband was born in Kincardineshire, and 1909, when Marjory was born, also in Kincardineshire, because she had six children already whom she could hardly have abandoned.
However it is quite possible that Marjory's father, name unknown but maybe Douglas, could have come from Fife.
Margaret Marjory Durnin was also illegitimate. Her father Peter Durnin absconded after fathering her and was last heard of in Glasgow. He could have moved at a later date to Fife.