So, I heard back from HR today and it looks better than it did. Turns out I was dealing with someone who was pretty new at this and didn't know all the ins and outs of how it worked. That's a huge relief. Thankfully, there does appear to be some wiggle room, and I know the Big Boss can make other things work if they need to.
As she said before, HR clears me through FMLA for any leave the doctor requires. That would all be paid leave. If I chose to take any additional leave, that would be up to my department. I just contacted the Boss and Big Boss (B and BB from here on in), and told them what I knew. HR said that if I made it all the way to my due date, there was some room for discussion/negotiation about how best to finish up the semester since it's in the best interest of the students to not have a sub for the last two weeks when major grades are coming in. I know the BB will tell me not to work at all, while the B wants me to work; for me, it will depend on what we negotiate. I don't want to screw over my students, but I don't want to stress out. Final grades are due around the 19th of December, so if I gave birth around Thanksgiving, that would give me about a month to collect a major paper for all classes and post final grades. That's not a lot to deal with (I kinda have grading those things down to an art - I don't fully comment on them unless the student requests it because most students don't ever want to pick them up. I'm not commenting on something that just goes in my trash.)
As far as teaching my online courses and being out in the spring for a few weeks, that's up to the B and the BB. They've already told me that's no big deal, so I'm not worried about that.
So, it sounds like things will work out pretty well. I don't get to stay out as long as I wanted to, but the bonus is that I will have some sick time in reserve for when I will eventually need it.
Thankfully, that takes care of a lot of my worrying. Whew! Now that I know we have room to play with this stuff, I feel better. Thanks for your concern :) Again, we'll be fine no matter how this works out, but it's much nicer when it's easier and not a big hassle - as is all of life.
I have a meeting scheduled with BB and B on Tuesday at noon to figure this all out. Fingers crossed that everything works out well :)