The 1901 census seems to have Margaret recorded as Margaret Polson or Stephen and a widow. ( This may, of course, be a fictional widowhood!).
This appears to be her death notice in the Aberdeen Daily Journal 7 March. 1913.
"Stephen - At the Royal Infirmary, Aberdeen, on 6th March, Margaret Cooper Stephen, eldest daughter of the late Alexander Polson, dancing master, aged 46 years.".
Interesting to note that her age is incorrect ( this can. of course, depend on the knowledge of the informant) as other evidence gives her birth year as 1861!
William