-I've seen a list of missions-eligible modules in the latest FAQ, but im wondering how many of them can actually be applied to season 5-8 of missions. For example, i believe Sprawl Wilds and Firing Line are earlier releases, and not set necessarily in Chicago. Can we still apply all of them after playing through them to our characters, should we want to bring them to a con play, or are some reserved for earlier seasons /prime-runners/other reasons only?
Everything in the current FAQ list is legal for the current SEASON (I use the singular season to refer to seasons 5-8), however, not everything has been published yet. You are correct that things like Firing Line are not in Chicago, that is fine (You will actually find quite a few that aren't in Chicago), if you or the GM can come up with logical reasons for the team to be traveling, that works great. In missions play at cons you frequently find yourself somewhere else with little explanation (That is a reality of only having 4 hours to run a module at a con, something you don't have to abide by at a home game.) You will also notice that a couple of the released module books come duel stated for 4th and 5th, don't worry, if they are on the list they are still legal, just use the 5th edition stats.
One of the few "regulated" missions on that list is Killing Pawn, it is meant for prime level play, which ideally means 150+ karma per character. However as the FAQ points out, playing it DOES NOT remove you from regular play, just means you can wear your big boy pants when you need to.
The only thing that arbitrarily removes a character from Con/missions play (Besides character death) is having rewards from non-missions legal modules, either ones you create yourself, or published ones that are not on the list.
-Can someone explain to me in layman terms the character record calendar? Is there a deadline to how many days weeks you can "Use up" before you run out or is it more of a bookkeeping aid without any real limits?
It is a bookkeeping aid, mostly for knowing when you have to pay another month of lifestyle. However I find it useful for keeping track of training times as well.
It is not a dead line, when you run out of one, just print out another year. (My main character is on year 3 now)
Here is a thread with a Calendar example, it's my example and only an example, use yours however it works for you.
http://forums.shadowruntabletop.com/index.php?topic=21126.msg379834#msg379834Hopefully this is what you wanted to know about calendars, if you have more questions feel free to follow up.
-Are convention play missions exclusive to particular conventions? For example, if we are starting missions now, and end up lucky enough to find some convention plays in Montreal where we live, would we have the opportunity to play through those older, convention only, modules? Or missed cons modules are missed forever-opportunities?
Play at whatever con's you find, that is the real point behind a living campaign. Every GM is supposed to run their table just like every other GM so players will experience consistency at every table they play at. The reality is that you will find some GM's that do things a little different than others, but they all want to make sure you have fun.
Unfortunately, no matter how big the con and no matter how many GM's are there, you may not find the mission your looking for, we simply have too many modules for us to run them all every time. But if you keep your eyes open, especially at smaller cons, you may find what your looking for. And cons may not be your only option, Many GM's run missions periodically at their local gaming stores and if they are a Catalyst Demo GM, they will likely have access to most if not all of the unpublished modules and you may be able to put in a request for something your looking for (I try to be good about that at the store I run at)
And in case it's not clear elsewhere, you do not have to be a Catalyst GM to run missions or give out reward sheets.
-Anyone knows if Montreal, Canada has any con events lined up/is there a calendar/registry somewhere?
The site is currently down, but when it comes back up this will hopefully help you find events in your neck of the woods, as for Cons, I would have to do some digging to find an answer for you.
http://www.catalystdemos.com/