Our first trip with both our kids, our DD was 2 1/2 (almost 3) and son was 4 1/2 (just shy of 5) and we also stayed 10 nights. It was great to have a longer trip so we could take it slow and go at their pace!
We took along our own double stroller (a nice tandem one that they could both nap in, and we drove so had tons of stuff in our van). They napped in it every afternoon that we were out, so we would just find a nice quiet place and have a beer or soda and relax. Bedtime was good, since honestly we were all pretty tired and just rested when they went to sleep. I hope that you can work out the sleeping arrangements! What worked out for us was first we tried to have DD sleep in the pack & play in the room (we were in a one bedroom Boardwalk villa) since she was really small for her age. Then we found it was better to have her share the big bed with me and DH and DS took the sofa sleeper (most nights).
We did some relaxing things - yes the Epcot kidcot thing was fun - they enjoyed making masks and meeting the cast members in the countries (don't know if they still do those, but if they do it's a nice fun thing to do). My kids really enjoyed Innoventions at Epcot a lot too! They still do. There is one area where they learn fire safety, and kids like that. It's good for even the little kids!
We never did any late dinners, dinner shows, or La Nouba - my kids were ready for sleep by 7 (DD) and 8 (DS) so it would not work. We kept a fairly normal schedule so they wouldn't get too tired and cranky.
At the Animal Kingdom, we could spend a whole day exploring the animals! Rafiki's Planet Watch is nice. They loved the acrobats there too - don't know when they perform, but all the kids seem to just be mesmerized by them.
I always use a sound machine too - and especially when we travel. Also, we brought along their "blankies" and I think early in the trip let each pick out a stuffed animal to cuddle. That helps!
I always kept simple snacks handy like Teddy Grahams and juice in my day bag (son has allergies, so I always had snacks with me anyway). Kids sometimes just want a snack not a huge meal! Also I kept a large ziploc bag with a change of clothes for each of them (including socks) in my backpack just in case. Spills happen.
We didn't do water parks when they were little, since the pools at the Disney resorts were really so much fun for them that it wouldn't be worth the hassle to watch over them at a water park. If I were staying somewhere off site that didn't have a pool I guess I'd go with little ones, but otherwise we waited till they were much older.
Many resorts have playgrounds too! One trip we were staying at the Contemporary, and right outside our room (we were on the first floor with a sliding door to the patio) was a playground. Perfect!
There is so much to do at Disney - we haven't done it all in all our trips. I would suggest taking it slow at their pace, and don't rush from one thing to another. Sometimes we'll be at Epcot just hanging out and a little band of those guys with trash cans will set up and play drums! Those who have been - you know the guys I'm talking about! If we were in a hurry, we'd miss it. Or "Push" the talking trash can. You never know what you'll see while taking an ice cream (or beer) break.
All the countries in Epcot have interesting things for kids to explore. From their first visit, Epcot has been my kids' favorite park. Okay, we're kind of geeks!
I hope I've helped, but know I've rambled. I just am excited for you, since our first trip was so much FUN!
