C.L.
Hi there!
Congrats on your pregnancy!
I have travelled a few times with my two kids, most recently in February to Australia from Denver via LAX. My son was 12 months and my daughter was 2 and a half at that time. It was tiring but fun. So, to answer your questions:
1. I don't know if AA allows pre-boarding, but most airlines do. They will board families with children after business and first class, generally. As for the car seat, I realize that it is probably safer to fly with a car seat, but we didn't. I have done it before with my daughter, but it took up a lot of space and was very uncomfortable and for that long of a flight, we didn't want to do that. My son was a lap child on that trip to Australia. We survived though! :)
2. We have always gate checked our stroller. Sometimes there may be room on the plane, maybe in the flight attendant's area, but that has never been the case with us. When you gate check it, they put it in the cargo hold last, so that it is readily available when the plane lands. It should be safe. However, we have had a stroller break when it was gate checked. I was travelling alone with my daughter when she was 5 months old. I got off the plane and they asked me "Is this your wheel?" and handed me the stroller wheel and said have a good day! I was not happy! That hasn't happened since though. So it is a risk you will have to take. The airline may reimburse you if that happens, although you never know nowadays with all the fee hikes...
3. You can take food through security. The drinks may be more tricky. From what I understand, the security guard has to be satisfied that you will need the amount of juice/milk/whatever for the duration of the flight. Bear in mind that you can usually buy juice and milk after you go through security. That's what we did. We carried empty sippy cups through. For my son, I filled his bottles with water and brought the formula powder. They took us aside at security and tested the water (they don't touch it. They just put a strip of paper up to it.).
4. We brought coloring books, some new toys and the DVD player for my kids. The flight to Australia was overnight on the way there, and my son slept, which was great. They provided a bassinet that hooks onto the wall of the plane. They gave us bulkhead seats also, which was very good, because we could spread out on the floor in front. The only downside to the bassinet was that you have to take them out every time the pilot puts on the fasten seatbelt light. The flight back was harder because it left at noon and was mostly during the day. The sun was only down for a few hours. The kids were up the whole time. Very tiring, but we made it! :)
5. and 6. I am not familiar with DFW, so I can't really help with this. We pulled up to the passenger drop off and unloaded there, then my husband went and parked the car.
The most trying parts of the trip for me was worrying about what other people thought. If you can get over that and not feel that you need to apologize for your kids, then you'll be fine.
Hope this helps!
C.