If you can, go down to the front desk of the hotel at 12:01 AM and ask them to print your boarding passes. This should secure you "A" passes. (means that group boards directly after the preboards). You will not have a seat assignment. It's pretty much a first-come, first-served situation with boarding. Get to the airport early, so that you are closer to the front of your "A/B/C" line. Check before you sit down 'cause you might choose a seat close to the gate, but it might be in the wrong A/B/C Aisle
They will most often allow preboards for families if they have a child 4 or under, although someone on the transportation board recently said they think it's now 3 and under. It was 4 years old in Jan. Don't know if you'd qualify, but since it's not guaranteed, try and checkin online at the hotel at 12:01AM to be safe.
Yes, you can bring food/drinks on board. They will provide you with a small glass of pop/juice and some little snack.
Where are you staying at Disney? DSis and myself are flying AirTran out of Buffalo on the 20th, and staying at POP until the 26th. Would have preferred direct flights on SWA, but at the time, AirTran was the cheapest and we just really wanted to get it booked.
We enjoyed flying SW in Jan, so no worries ... it will all be fine. And there's most likely curbside check-in at the airport which is really nice and convenient.
Have a great time ... maybe we'll see ya there!
MaryLiz