I wore my second baby almost constantly for her first 18 months, so a little bit of experience, including a disney trip when she was almost 2.
For a newborn / infant a ring sling is hands down the most comfortable, versatile, inexpensive carrier. My very favorite was a small business handmade carrier from sleeping baby productions. She also has some fantastic videos and tutorials on how to use a ring sling. The key to a ring sling is learning to use it properly, both for your comfort and baby's safety. My very favorite position with dd was her held facing my chest, snug her legs up and under, tighten the sling around her bum and back. When she was sleeping I would just pull the fabric over the back of her head and snug it up to support her head (always make sure you can see their face). Hands free to chase the older kid, or whatever you need to do. Baby in a nice, snug, curled up position, feels nice and safe. And it puts baby's head right at what I always called kissing portion.
A mei tai style baby carrier works well for a small infant too, but is a little more fidgety, and a little more work to get right.
I would not personally put a 2 month old in buckle carrier. Once they are old enough to have some muscle control and head control a front carrying buckle carrier is fine. Once they have full head control learning to get them in a back carry in a mei tie or soft buckle carrier is invaluable. Especially for a clingy kid.
There is a website called the babywearer.com that is full of all sorts of great information. Even if you don't plan on baby wearing regularly, and just want info on a good carrier for your disney needs it might help.
I have a lot of personal experience, with a lot of different carriers, feel free to ask me questions. My personal picks are:
For a newborn infant a ring sling. My favorite came from sleepingbaby.net, but I made several of my own as well
For an older infant a mei tai carrier, my favorite was baby hawk, but I alos made one of these.
Once baby has complete head control a soft structured carrier (buckle or tie) with a sleeping hood is invaluable. My absolute favorite was a brand called Bamberoo, but they are expensive and difficult to get due to the fact that they are one of a kind, hand made items. I also owned an ergo, which I found ok, a kinderpack, which I liked a lot. A ring sling can be great at the older infant and toddler age for a hands free hip carry as well. Good for quick in and out trips, and on and off rides. Getting baby in and out of a hip carry with a ring sling can take seconds once your used to it.
I would not, however, recommend taking a carrier with you that you have never used and expect it to go well. Get both you and baby used to it at home, and you will be a lot happier in the long run.