You will have a wonderful time with your dc. My youngest will be 14 months for our October trip, so I've been thinking ahead to that.
Flying trips: Have you bought your dc a seat? I highly recommend doing so and bringing along your carseat. We made the mistake of having our dd be a lap baby for our first trip, and it was a very looooong 2 1/2 hours! It's hard at that age because they want to be up exploring, and don't get the concept that they have to stay seated. If they have their own carseat, they already know the stay seated rule from being in the car, so it's not as huge of a deal. Bring along plenty of snacks, books, small (and quiet) toys.
Park Tips: Go at your baby's pace! This is a nice age because they don't know what they are missing if you don't do everything. Definitely take a nice, long afternoon break. Keep dc hydrated, and use plenty of sunscreen. My dd kept herself entertained for the longest time in the fountains at Epcot, so be prepared to stop touring for any of these unexpected breaks. I'm working at weaning ds off the bottle around his birthday. I don't want to have to mess with bottles for our trip. Bring along plenty of juice/water and a sippy, and plenty of snacks. I try to travel lightly to the parks. I keep essentials in a fanny pack, and then I bring along one of those stroller bags instead of a diaper bag. That makes life so much easier. If you're only park touring for 1/2 day, and then a break, you won't need to pack it as full each time. Oh, and I second bringing your own stroller!!!!!!!!!! Bring along a stroller cover and a stroller fan.
We've never done the water parks, but I'm sure there must be one with a zero entry pool. Those are wonderful for babies!!!!
Oh, one tip I can share is to always bring along outlet covers for the resort!!!
Have a great trip.