Nope. NOt included. Included are ice cream novelties from the carts, sodas, water, chips, fruit, mickey rice crispy treats at most hotels but not at the Main Street Bakery in MK. Some counter service places will have more latitude. Resorts will also give brownies and cookies as a snack. Starring Rolls at MGM counted a cookie or donut as a snack.
I have found stands that sell just a specific treat such as Funnel Cake, Dole Whips, Kaki Gori, etc. These are NOT on the dining plan.