Item one, how long is this campaign going to last?
Haven't thought about this too much myself, as it really doesn't matter too much. As long as the story is engaging (and it has been), the scenarios are interesting (and they have been), then I plan to show up and play BT. Maybe it was originally pitched as a Fall/Winter campaign, but I think that might've just been a way to distinguish it from the "Summer" Solaris campaign. I never actually had an expectation that it would end within a few months.
Our group hasn't really operated on a set time-line before (other than the Solaris campaign). Our previous clan campaign ended when the GM decided it was time to do something new (possibly he felt it had started to grow stale, or maybe he wanted to end it before it did). The most recently concluded campaign ended because the failure of the btechunits.com website effectively erased our records (extensive), and our fiction (which really was exceptional, imo, considering that we don't truly run a rp campaign). We were all (I think) having a great time, I know I was having a blast GM'ing the Farwell contract, but when everything went up in smoke it was mutually decided that it was as good a time as any to start over with something new.
So, now we're in Travis' and Mike's Jihad campaign, and it's possible they've got an end-date in mind, or perhaps they've got a certain story path mapped out and how fast we reach the end depends on how often we play. Considering we've got more Jihad publications coming out this year, it's as good a time as any to play in, so if we stay in it for another year or longer, it's fine with me, and if it ends in March, that's cool too.
Item two, what pace are we going to continue at? I believe the initial target was to play two campaign scenarios a month. So far, we've been doing one scenario a month.
Fair question, and I think you've outlined a lot of the reasons that we've slowed down. For myself, I'd love to play every weekend, assuming I also had infinite amounts of time available for my family, job, sleep, and other pursuits. Sadly, my time is a lot more limited than that. As much as I love to play BT, I've come to the realization that about once a month is all I can really spare (if we're talking about a full Saturday gaming session), and I'll enjoy other parts of the hobby from home like reading sourcebooks/novels or painting minis. I might fit in an extra day every now and then, but not often. Others have got different circumstances, like yourself, so I've got no problem with the group scheduling games more often; I'm just saying I won't be able to make all of them. I'd guess that sometimes the GM's find themselves short on available time as well.
As a suggestion, if you see that we can't play a campaign game for a few weeks, try to schedule something yourself for a different weekend. No doubt you can get a few people together for a gaming session.
This works best if you don't simply say "Hey, let's play a game on the 15th, bring some sheets!"; instead try coming up with an interesting scenario (or easier yet, steal one from the scores of available sourcebooks/chaos tracks/etc) and make a post more along the lines of "Game at Sci-fi 1/15: Gray Death Legion ambushes 4th Skye Guards!". Post up the details of the scenario (lifted from HTP: Glengarry, of course), ask who can make it, and what faction they'd prefer to play. You'll definitely get some takers, and while it won't be a campaign game, it'll be every bit as fun. Plus, for that day, YOU get to be the evil GM.