OMG, so do you all sit home like hermits after a baby is born? With a 5 and 2 year old when my last son was born, I had my DD's school and all kinds of stuff I had to do with him. He'll be a year old tomorrow and has never so much as had an ear infection!
Life does go on when you have a baby amazingly enough. And they are very adaptable. It is easier to take them that young than when they are 6-7 months old and wanting to crawl and get down everywhere! YUCK! At that age, they just want to be held and that's what you do while you're there. Changing diapers at DL is no different than having to change them at home. You still gotta do it!
Going to bed early isn't a factor because they most of them aren't on a schedule yet anyways and don't care where or when they sleep. Also my son and daughters have been on all the rides I listed above as infants with no problems at all. Many infants go on them everyday, they are perfectly safe for them or they wouldn't be allowed to ride and there would be a height requirement.
Also should my world just stop when I have a baby? Should the older two have to miss out on DL for years and years, or should I have stopped at one so that I didn't have to take an infant with the others? And no it's not an option to leave the baby home since I exclusively nurse, and I wouldn't leave a member of the family behind anyways no matter how old. I would never put my kids in any danger, and I don't feel like they were. If you can ride the ride pregnant, you can ride with an infant!
OP, it's easy to keep the baby close to you. At that age, they aren't grabby and touchy so they won't be getting germs that way. No high chair germs to worry about and you'll have your own stroller so it'll be clean. Face them towards you in a carrier or a sling and you won't have people breathing all over them. They are just as fine as they would be when I help out in my DD's class party after he was born. Life goes on.
Also as far as loud noises, my DD's play and yell louder at home than most of those rides are. You can easily cover there ears for a while on certain things if need be. I never found it necessary except on Jungle Cruise where the gun shoots the hippos. He was asleep and didn't even jump when the gun shot. He had no clue as he was dreaming away.
I also hate the memory argument. I don't take my kdis for the memories. I take them because they love it there and so do I. Should I never take them anywhere before they are 5 or 6 in case they don't remember it? Should they not go to the park, movies, minigolf, water parks, birthday parties, DL and sit home for 5 years? If it's a once in a lifetime trip, I would probably wait a little. But if you will go more often, go, have fun, and make some memories for yourself!!! That first character interaction is priceless at that age, and the characteres LOVE babies!!!
Have a great time and don't let anyone scare you. You'll be fine!! Take lots and lots of pictures!