Here's what I have on my list when making the budget.
Tips - airport parking, baggage handler, bellmen/ or if you store your luggage before or after check in or check out, for dinning, and adult beverage stops, and house keeping. Tips for taxi, uber, lyft...
Souvenirs you can spend a lot at Disney on these, so be prepared. Here's what we did each DD would get 50.00 on a gift card and when it was gone it was gone...when they have to spend their money they are more aware of what they are spending it on, and we would by them each a T-shirt not part of the 50.00.
Not sure now long your flight is, food and drinks on the plane...
Food - depending on which dinning plan that you have, you might need to buy a extra meal here and there, or extra snacks or drinks. Dinning plan credits are good until midnight on check out day, so plan if you will need breakfast or even lunch. Make sure to spend all your snack credits, possibly on pastry or muffins for a quick breakfast, or spend the night before for items to take home. Even if you don't normally eat a lot or the kiddos don't, with a lot of walking and excitement you will find yourself needing more food. Check out the menus and see what might be good for you to share so you can manage your entitlements to the fullest. I strongly suggest having water delivered, and bring some snacks with you to keep on hand, A lot of folks use Staples for water delivery. Garden grocer will deliver to the resort, or you might want to get a Uber over to a store for some room snacks and water.
Adult beverages - plan on around 15 to 20+ plus tip per round for 2 adults.
Poncho's, sunscreen, sun-glasses, over the counter med's - make sure to have these with you they are pricey $$$$ at the world.... Bathing suits, flip flops, are other items that needs to be in the suitcase.
I always pad the budget, so I am prepared. Anything leftover goes toward our next trip.
I would make sure you have some emergency funds available for the just in case's, whether in cash or credit cards.... access to both. My friends had to go to a walk in clinic, which was 150.00 for the visit as she forgot her insurance cards, luckily Walgreens had her insurance info for the prescription her part was under 20.00 bucks. Then the added cost of the uber ride there are back... Another friend forgot her allergy shots, and had to go to the ER, and they had to paid like 300.00 right then.
Have a magically trip, Peace, Love and Pixie Dust...