Several restaurants have appetizers or desserts for two. Some will let each person order their own (i.e. Mama Melrose), but most require two people to order it and take two credits for that particular dessert (or appetizer, if you are on the DxDDP) (i.e. Grand Floridian Cafe). It just depends on the restaurant. Other than those items specified as serving for two people, there should not be any restrictions. Alot of people ask about the surf and turf at Narcoosee, because it is probably the most expensive item on any WDW menu at $72.00. Yes, you can order that too on the
DDP (of course Narcoosee is a Signature restaurant, so takes two credits). Another question that gets asked alot on here, is since the Signature restaurants take two credits, do we also get an appetizer there. The answer is no. If you are on the basic DDP, then even though a Signature restaurant takes two credits, all you get is an entree, dessert, and a beverage.
Some restaurants also have a chef's price fix option on the menus that include a small list of appetizers, entrees, and desserts to choose from. That option is usually in a little marked off box on the main menu. Even though they include an appetizer not ususally included on the basic DDP, people on the DDP can order them. They are usually the cheaper items on the menu though and they allow absolutely no substitutions if you order from that section. However, if you like those items and would be ordering them anyway, they are a really good deal on the DDP. Also some restaurants have additional side items marked at the bottom of the menu. Those items are not included in the DDP. If you don't like the side that comes with your entree, they will usually let you substitute another side that comes with another entree, but will not let you substitute one of those extra sides listed at the bottom of the menu. The two exceptions I have had with that though is at Artist Point and Yachtsman Steakhouse. They allowed me to substitute one of those exrra sides at the bottom for the side that came with my entrees, but I would not count on doing that though. I know Le Cellier for sure will not.
Oh, one more thing: if you book one of the Fantasmic pkgs at Mama Melrose or Brown Derby, you also get an appetizer, even on the basic DDP, because it's included in the Fantasmic pkg.
Sorry, I gave you alot of info you did not ask for, but those questions get asked alot by people unfamiliar with the DDP, so just thought I make sure you knew.