Just to add a little about the aunt, Mary E Harvie.
She appears to have died in 1922 and left a will
Harvie Mary Erskine or Strang, Erskine Villa, Duntocher, Dunbartonshire,died 1 November 1922. Confirmation to James Risk Paterson, Rev James Hyslop, Walter Harvie, Robert Strang 15 Montrose Street, Ethel May Strang 15 Montrose Street and William Murdoch Hay.
There is an eik to confirmation in 1925 - the named executors are the same except Ethel May is now showing as Ethel May Strang or Keillar c/o Goodfish Lake, Post Office , Alberta, Canada.(Presumably now married).
Wills can be a great way of finding family relationships. Wills up to 1925 are available on Scotland's People.
William