I'm not really sure what you gain here by obscuring the countries, but it's possible that you'd need to present valid travel docs for Canada when checking in for the first flight of your return itinerary, even though that flight isn't to Canada. It's normal to check docs for the entire trip at the first point of embarkation to avoid having travellers stranded or denied boarding midway through a trip (and then incurring costs to the airline to return them).
As far as whether countries check API data to find dual citizenship violators, that's a question that's really beyond the scope of FlyerTalk.