Hi everyone!
I wanted to thank all of you SO MUCH for all your replies and advice! I wanted to check back in earlier, but got so got up with personal stuff, the holidays, etc. - I haven't been on the boards at all! 3 months have passed, but I wanted to make sure I report back with my "pregnant on cruise" experience, hopefully it will help someone.

We had a fantastic cruise!!!
I couldn't read the last replies to the thread - Jahber - we would have loved to meet you and your family, but we were already traveling when you posted, so I missed you guys!
So here are my personal observations and opinions:
Prep:
-I did get a last minute note from my OB stating how many weeks pregnant I was and that I was OK to travel.
Nobody ever asked to see it. (but I would take it again, just because you never know)
-We did already have
travel insurance, and pregnancy conditions were included (I had shopped on
insure my trip dot com and we picked "travel insured" - it was a great plan including medical and medical evac and hurricane/severe weather, and the price was very low in my opinion)
-I had filled prescription nausea medication from my OB as a standby, and I also had some over the counter remedies that were recommended here and elsewhere, like the seaband, and some ginger lozenges... etc. I ended up needing none of it! We were very lucky with the weather. It was stormy when we arrived in Florida, but cleared when the day to board came and the cruise was super smooth.
Airports and Flying:
-I kindly refused the full body scanner, and was instead singled out for a triple manual inspection in two different locations with chemical clothes analysis and what not. Great! My toddler was screaming in the distance wondering where I had disappeared to - not a nice start to our vacation, but in the end the TSA apologized and said the initial equipment that had alarmed on my manual was apparently not working right - after they brought in new wands etc. voila - I was clear. The rest of our air travel was uneventful. I didn't have the bags someone recommended, but plenty of plastic bags, and ziplocs, and the flight was calm, thank goodness.
Cruise:
-as mentioned we were lucky with the weather and the seas were calm - no nausea meds were needed
-I just avoided some foods that I was careful about anyways - cuts of deli meats, and some things like that, and foods that make me queasy, but of course there was plenty of foods to choose from, and plenty of drinks (yes, lots of tea choices as well - thanks to the poster with the pictures!), and all was delicious - and well I gained 5 pounds!

-we did our own excursion on Cozumel - we took a cab to one of the resorts there. The stretch of beach we ended up at was not my favorite, but they had a great pool. It ended up raining and we went back to the ship - I was glad we hadn't paid for a full day beach day excursion
-on castaway I went snorkeling (without diving) - and I overdid it a bit physically - the distances are deceptive, it's quite a large area! ...and people are so right to be extra mindful of hydration, that's true anyways on Castaway, but especially when your pregnant!
So I took it really easy the rest of the day, and made sure to drink a lot of water.
I can't think of anything else particularly related to traveling and cruising pregnant, but if anyone can think of any other questions, I will gladly check back here to answer!
If anyone is interested in our take on the Port of Miami/transfers, or how we experienced the kids' club with a 'just turned three' year old, I can maybe relate it here quickly as well without straying too far off topic...