I am also chasing this line and struggling over the McGlashan/Fraser issue.
I am the great great granddaughter of Donald Fraser (1826-1901) through my mother. Donald was the brother of Mary McBean, born Fraser (1814-1888). There were ten children of William Fraser (1782-1850) and Margaret McIntosh (1782-1857)
I did see a record of a William McGlashan marrying Margaret Fraser (born McIntosh), will look for it again as I can't remember the date. could they have remarried under her married surname and his alias??? I have a solid gold wedding band from my late mothers jewelry that she never knew where it came from, perhaps a new ring for the second wedding. It is a double band merging underneath to a single band. Just tossing around some crazy thoughts lol.