Hi Briana!
Sounds like you've got quite the Walt Disney World vacation planned! How exciting! I remember well the "I want what Big Brother is getting!" stage. Your little one will eat free at Buffet, or Family-Style meals, and he'll get to choose from the same selections as Big Brother. All other Table Service locations, you'll be able to order his meal off of the same children's menu as his older sibling at your cost.
At Quick Service locations, you'll be able to purchase him a meal "just like Big Brother's" as well.
As far as wagons are concerned, they are one of the items not permitted in the parks. You can read more about
Restricted Personal Items for Disney Theme Parks and Water Parks. Even if they're not fond of strollers, I might go ahead and bring one, especially for your 2 year old. A few hours of walking in the parks can make them
mighty tired, and a bit more open to
other options.
Have a magical vacation!
Amanda