I know Jim is only working part-time in the office, but it seems like he's on the show just as much as ever, if not more. Andy's absence is more notable. He hasn't been on at all in what, 4-5 weeks?
I sincerely doubt they'll break up Pam and Jim. More likely, Pam will be tempted by the sound guy but realize that she truly loves Jim when push comes to shove. I also expect they'll move to Philly permanently in the finale.