biggest baby tip: owners locker. You can have a grocery delivery service or
amazon deliver diapers to your room so you don't have to pack them, then leave the balance in your owners locker. Same with swimsuits for mom & dad, toothbrushes, baby sunscreen, first aid items, wipes, etc. you just have to do the math to determine how big your kids will likely be next trip, i just used their growth chart and added the months to figure their likely pound range for this trip to ensure they'd still be in the same size diapers. If you can swing it, I'd really try for a 1br. You can put the pack n play in the living room and not be in the same room as a noisy sleeping baby. Consider the very walkable resorts--for example Saratoga is walkable to Downtown Disney. Since the stroller will easily lull babies to sleep, that is a fabulous place to go because the point value is good and you can browse the shops, grab snacks, catch the 'street' entertainment all while the baby peacefully naps, or just looks around. Boardwalk is another good one--weirdly, for the first few years you want to pick resorts that are inherently entertaining to you. Save AKV, BC, and the other heavy kid hitters for when the kids do more than eat & sleep & look around. The kids clubs all start at 3 & potty trained, so look into finding a babysitter you like down there. The services are expensive and you don't get any choice in your sitter, so we used Sittercity to locate someone with great references. She is $20/hr for two kids which is on par or cheaper than the services, and we were able to check her references. Care.com likely also has Orlando listings. She has APs for all the theme parks so she can even join us there or take the kids if needed. So far we have only used her for a date night or two per trip but I think it seriously enhances the trip to have a night out --and for that I recommend JellyRolls

Until the baby can play/talk etc, don't plan too much around their entertainment because they just aren't going to get it and it will be just as entertaining to do something you like. Use the local zoo as a test--if they watch the animals and seem to be interested in exhibits, great. We found until about 14 mo all that interested them was fish tanks--instead of looking at the giant elephant, giraffe or chimp, they were watching little kids nearby or us. We are trying the MK and AK this trip with the girls at 17 mo so I'll let you know how it goes. They are much more aware and interested now so I am hoping they will be engaged. The focus on the early trips should be relaxation and togetherness more that touring, IMO. Ohhh!!! They love singing, dancing, clapping--we took them to the Hoop de doo for their 1st bday and they LOVED IT. They were banging on tables with huge wide eyes and grins. Totally worth the $ to see those little faces. They also get a huge kick scurrying around the villa. It is fairly childproof so we let them zoom around nonstop exploring. Abuse the free-ness---these are the last years of family fun at 2/3 or half price. Those kids get in free till 3 I think, and I think they are free on planes till 2 if you pop them on your lap. Time your flights with nap time and have them nurse or bottle feed at takeoff to prevent ear discomfort. We did this last time and they slept like babies. They loved characters at 12 mo. They have a little more stranger danger now so I can update as to how they are this trip, but we're doing two character meals so I am hoping they are still excited. They were leery of Santa this year although no tears or overt fear.
If you drink, save money & enhance your vacay by buying (again from grocery delivery person like WeGoShop or if you have a car, the liquor store) your favorite drinks/mixers... when those tots go to sleep you can grab a cocktail and sit on your balcony for sunset and parent time.