Meals, aside from the feast and ploughmans platter, are on the plan. The teas, ciders, pumpkin juice, and maybe fizz are your drink option that comes with the meal on the plan. The desserts and butterbeer are a snack/beverage. Breakfast already comes with a drink, plan or no plan. This makes it not as good of a value with the plan.
A better use of the dining plan is the $19.99 combo at Monsters with the $4.19 freestyle single serve drink. I’ve read it’s enough food for 2-3 people too, depending on appetites. But the 16.99-17.99 meals in the wizarding world with the 4.99 pumpkin drink are one of the most expensive options, just not the most expensive option.