Canada could also build islands on its coast.
No islands in Canada.
Well, that didn't take long.
Canada could build new city to Arctic (north of Arctic Circle).
But why when there is so much non-Arctic space available to build upon?
Because there are no major cities north of Arctic Circle in North America, compared to Europe. This city would have over 100,000 people.
Nope, you're wrong. This city would only have 64,500 people. Not even close to the 100k you claim.
Why would people move to the Arctic Circle en mass when they haven’t done so already through the entire course of Canadian history?
Have new point of view on life beacuse this city would see midnight sun and polar night which only very few North American populated places see
Right. They haven't already moved there because they've never heard of midnight sun or polar night. After the city is built, they'll suddently learn about it and want to go there. Not just for a week, of course, but for the rest of their lives. I agree, that outcome is pretty much inevitable.