1921 Canadian census shows different years of immigration for Stewart (1873) and Sarah (1878); so, this suggests a marriage in Canada, rather than Ireland. The 1911 census gives the same information.
In the database of the Toronto Emigrant Office Assisted Immigration Registers (Hawke Papers), I find a Stewart Hull arriving onboard the Polynesian on June 27, 1877, Irish, bound for Orangeville. Only one person in the party (ie, travelling alone). He is indexed as "Hall" on Ancestry.ca
Also, Elizabeth Ann was baptized in Hornby, Bruce County, not Halton County as I posted before.