I'd really like to know the answer to this as well. It will determine whether we go there or somewhere else to celebrate our 20th Anniversary! Can anybody help?
The steak and lobster entree is included in the dining plan. What would have to be paid for OOP are the items farther down on the menu in the "Enhancements" section if you decide to order any of them.
Narcoossee's Steak and Lobster Tail is included in the Dining Plan. I've ordered it. Note the Lobster Tail isn't Maine lobster. There are no entrees in WDW that are excluded from the dining plan that I'm aware of. However, there are some prix fixe meals (several courses at a total fixed cost) at certain Epcot restaurants which require an additional charge if using the dining plan. Narcoossee's doesn't have prix fixe offerings (to my knowledge).