I only know the 1 answer, and this guy ^ was right.
Anything that fires over 500 FPS is considered a firearm in Canada.
Although, importing a gun into Canada shouldn't be too bad, cases of airsoft guns being permanently seized by Customs are rare.
Also, about the orange tips, there is no law stating that they must have them in Canada, they're given that because they're all made in America. BUT, many police officers think there's a law. I personally have asked 3 different officers of the Peel Regional Police, and 2 have stated that it's not illegal to have a gun without the tip, albeit a bad idea. The other one stated that it's most definitely a crime to not have the orange tip.
Truth is, airsoft is still really fuzzy when it comes to Canadian laws, because of how much they look like firearms.