While there are others who can better fill you in on the possibility of getting your guns into the country, I can help settle a few of these for you.
Owning and buying: if the airsoft in question is already in Canada, you can buy them from retailers without any special permits or the like. Some retailers will insist you be at least 18, some don't. Importing guns from outside Canada is another can of worms.
FPS limits: CQB /indoor is often limited to 350 FPS on .2g bbs. Outdoor is usually 400 FPS, but can go a little higher. There are special rules for DMR and sniper rifles that can allow them to usually 450+ fps with a minimum engagement distance.
Blank fire stuff: up to the site you're playing at. Some will allow cold or hot burning smokes. Again, you're going to have a problem getting some of this stuff in Canada due to various weapons policies.
Transporting: if someone sees you with any weapons and calls the cops, they're going to treat anything you have like a real firearm. People have been shot for being stupid about this in Canada and the US. Use common sense: cases/bags to hide airsoft guns, not wearing your full kit in public, etc. Some public transit authorities in Canada actually have specific regulations regarding the transport of airsoft guns.
Weight restrictions: usually no. The only restriction tends to be using .2g to chrono with. After that, restrictions tend to be whether or not the site is Bio BB only. And of course pretty much everywhere bans the use of silica bbs.
Fire rate: again, site dependent. Some indoor places will have you do semi-only, some allow you full auto. Most places frown on extended full auto unless you're running a support weapon. Again, this is up to the sites/groups you will be playing with.
Eyewear and face protection: No mesh goggles (lower face mesh masks are fine) tends to be one of the biggest restrictions. Goggles must be ANSI/Ballistic rated. Some places, especially paintball ones, will also require full seal goggles rather than just shooting glasses, while others will allow you to wear rated glasses instead of goggles. Check the rules for your preferred sites.
Hope that helps!
Edit: several answers came as I was typing this, I see. Guess all we Canadians are eager to help out!