Yes, I get what you mean.
You had the big ones with the luggage, and an extra bag for what you take home. I have always purchased a large bag with handles from the gift shop for like $5 and we load it up on the way home and take it as a carry on. Some of the things you will carry on with your trip down, you can just pack and check for the way back.
With your kids being so young I would try to estimate what size they will be come december and get a couple of the warmer weather stuff, just in case you cant find it come december and they have out grown where they are this summer. (we had that happen)
Dont forget a waist pack aka. fanny pack for each of you. It sure beats leaving a purse somewhere. We actually get the kids size ones for our kids, at check in each of your kids will get a plastic room key. My oldest is 4 and he loved to get into the elevator and get his room key from his own fanny pack and open the door for all of us. We also save up through the year by purchasing disney dollars from the local
disney store. We get $100 per month and we use those before we use green cash or plastic. It keeps our savings true savings and they will let you exchange it back in for green cash at the end of your trip if you need to. However if you use a $10 for a $2 item they give you green cash as change. FYI......so what we also do is each morning when the kids get their fanny pack on we will give them some disney dollars for in it. We use to give them a couple of $1 now I give them a $10 but it makes the kids feel independent.
The poncho is another great idea so you dont have the extra money to spend down their.
If you plan on brining strollers at all, I recommend getting a rain cover for them. Not only is it good for the rain, it is great for wind, Epcot gets very windy. It is also good to cover the stroller if it looks like rain, and you are headed into a show.
Sunblock is hard to find around here in the winter, so buy it now and put it away.
I go and get the travel stuff that you would always get, but I do it the way you are. I get a few things each time I go to the store and I put it away. If you get one suicase and stick it under the bed or in the closet, every time you come home with stuff, stick it in the suicase. One time I packed and I couldnt remember where we had stuck the bags......it was months prior.
We also get the travel bubbles. You know the real small ones that you might give out at a wedding instead of the rice. If you go to
walmart they have it in the craft section as a box of 50. We put one in each of the fanny packs for each day. When the kids are tired of waiting in line or sitting on the bus or boat or whatever, we pull out the bubbles. It works for the 5 or 10 minutes you need. I have also pulled them out and blowed bubbles at my kids to get the kids around us to stop screaming.......it works on ALL the kids VERY VERY well!!!!!!!And everyone listening to the screaming appreciates it.
Dont forget to get sunglasses for your little ones, they need them too!
I will have to think on more.......I will let you know if I ome up with any!
Good Luck, and have a magical trip!!!