1) Maybe. Would require discussions between NATO and an independent Alberta. Till that is done, NATO protection of Alberta would only consist of what's necessary to protect the rest of Canada and the USA. -- Theoretically, someone (say China or Russia - dunno, don't question, this is an unrealistic hypothetical after all) could request permission from Canada and/or USA for overflight to allow the bombing or airborne troop deployment against Alberta. Of course if it ever got to that point, Canada and/or the USA (probably with First Nations' support) would do the job themselves.

2) Procedures and some personnel would likely be changed. Actual crossing points would probably remain unchanged until addressed separately.

Let's see,
1) gunman rushes a secret service checkpoint
2) multiple shots are heard
3) suspected that gunman got at least ONE shot off before fire was returned
4) only person hit was an officer in their bp vest (1x)
5) last 3 information I have says forensics STILL trying to determine source of that shot (FF?)
6) gunman subdued without being shot (reports fail to mention taser use; assumption: it wasn't)

Honestly, we are expected to believe that a group of highly trained and dedicated security personnel firing multiple shots at close/PB range vs. an observed armed threat that may have already discharged a firearm while actively breaching a security checkpoint in close proximity to the Pres, VP and other high value admin. officials ALL MISSED with the possible exception of hitting one of their own.