From what I can gather, Canadians do have a Christmas cake, and it is a fruitcake similar to the British one that can be glazed or iced. However, is this true for all of Canada, or is it regional? The Stargate: Atlantis character is from Canada, but could be from pretty much any area of the country (though probably not Quebec!), so if it is regional moving his family to that region is no major problem, canon-wise.
I hope this is okay to ask, seeing as I'm really looking for confirmation of research, but I have made errors before by relying on solely on net research!
EDIT: I've decided to give the character (McKay) a British grandmother who came over as a war bride (as suggested by atdelphi), and not mention where in Canada they live. That should will cover any cultural problems. Thanks everyone!
(Am I the only one that all this of cake and other sweets has made hungry?! *g*)