Hi there, Nicholas!
Without exceptions, if a restaurant is participating in the
Disney Dining Plan, any entree would be order-able, and you'll be debited only the requisite number of credits.
At
Narcoossee's, for example, there is a "Butter-poached Maine Lobster Tail with Grilled Black Angus New York Strip" currently priced at $72.00 (prices subject to change without notice). This would be eligible for purchase on the Disney Dining Plan.
This is true for non-alcoholic beverages, as well. If the beverage is listed with the rest of the standard beverages on the menu and is not accompanied by a glowing character, or served in a special cup, it will fall under the guidelines of the plan.
Make sure that you check in advance, however; some restaurants do have disclaimers which can be gotten ahead of time by calling (407) WDW-DINE.
Have a delicious trip!
See you later, celebrator,
-Deborah B.