I'm currently 24 weeks pregnant with #2 and am on Humira. I too was on Imuran when pregnant with #1 and she was/is perfect and healthy.
I'm not sure if I'll breastfeed or not. I had supply/latch/PPD issues with #1 so we'll see what happens this time. I also haven't discussed that with my GI, but plan to at my appt on Monday. I'm almost positive that he'll tell me it's fine.
Was your OB skittish about you being on Imuran with your first? Mine was but deferred to my GI. With the Humira, he didn't even offer an opinion, as he knew I had already discussed it with my GI beforehand.