Yeah, Kinder Surprise is illegal in the US because the government decided that the toy surprise inside the egg poses a choking hazard to children. Guns are A-OK, though, because FREEDOM. Or something.

Honestly, I wouldn't worry too much about the prices in Canada. With the strong US dollar, everything you'd want to buy should be comparable to what you'd pay in the US or in some cases, as has been mentioned already, significantly cheaper.

You can definitely get maple syrup at a reasonable price. Other options might be maple liqueur (I personally like Coureur des Bois maple crème liqueur), ice wine or ice cider from Quebec, Canadian sports memorabilia, etc. You can still find lots of Expos stuff for sale in Montreal even though the team no longer exists.

In Montreal, you should check out the Marché Jean-Talon. It's a massive indoor/outdoor food market, but they also have people selling other random things like homemade soaps, etc. Even if you don't buy any gifts there, you can get delicious things to eat.