We took DS for the first time when he was 14 months, so not quite an infant anymore, but it was a great age to go. A lot of people we know couldn't understand why we'd want to take such a young kid to WDW but we love going and were really excited to take him. It was so, so worth it. Some thoughts based on our experience:
* Some people swear by baby ear plugs for the plane rides so we got them and it turned out he didn't need them. It's something easy to get and bring with you just in case though.
* Having a comfortable stroller that can recline with a big canopy was really nice for having him nap on the go (we brought our City Mini with us). It's good to have some way to mark your stroller so it's easy to find it among a sea of strollers.
* Lots of snacks for the plane ride and to bring into the parks was key. We have an insulated saddlebag that attaches to the side of the stroller and it holds an amazing amount of stuff like drinks, snacks, sunscreen, etc.
* You'll know as you get closer if babywearing is still an option. DS didn't really like being worn after the first few months.
* We packed things like diapers and wipes with us since they got used up and that luggage space became souvenir space for the trip back! Once you get there, you can use a service like
Amazon Prime Now to get some grocery items delivered to your resort if needed.
* Since you won't have a car, they may be times where you need to get somewhere quickly and don't want to wait for Disney transportation. I would recommend setting up the Minnie Van service on your phone so you can use it if needed - it's $25 one way within Disney property and they have car seats guaranteed. It's still cheaper than renting a car for the whole trip and can help you out in a pinch.
* We brought a silicone placemat that we would just wash after restaurant meals. This along with one of those silicone pocket bibs worked really well for us and we didn't need to change his clothes while we were out since he didn't really get messy.
* There are great play areas that aren't necessarily rides - the Dumbo ride queue has a fun playground as the waiting area, there's a little play area at Splash Mountain, AK has the Boneyard play area, the aquarium area at the Seas Pavilion, etc. I'm sure there are more that I'm not thinking of right now!
* Shows can be really fun at that age! DS loved the Festival of the Lion king show in particular.
* Some kids love the characters and others are terrified. Depending on how things go, character meet and greets might take up a lot of your time or not much at all. We did end up using some FPs for character meet and greets since sometimes those lines can be crazy long (like talking Mickey at MK).
* We planned for a balance of time in the parks and time visiting various resorts and just relaxing. We made sure we were all well rested and not on the go nonstop. Sleep/rest + snacks + play = a happy kid = happy parents.
* Memory Maker was so valuable for lots of great family photos (typically much better than what you'd get asking a random stranger to take one for you). Sometimes we would get a really enthusiastic CM who was great at spending lots of time with us and making DS smile.
* Enjoy whatever restaurants you want (I think the only one that doesn't allow kids is Victoria and Albert's) since there will be other kids there, and Disney is a very forgiving place to bring your kids to nice table service restaurants.
Whew. That was a longer list than I anticipated writing
Have an amazing trip and hope some of this was helpful!