Flyinf Fish is two credits, not one. It is a great restaurant, though. You may want to give up a breakfast or lunch in exchange for this. In general, that's what we did in the past on the DxDP -- mostly two meals a day, with a deluxe for dinner, and either TS lunch and use snack credits for muffins as breakfast, OR big buffet breakfast and snacks for lunch.
As for sticking with one credit, you already have a visit to the Poly planned, but Kona Cafe may be my favorite 1 credit right now (although we stopped getting the plan and it's definitely worth out of pocket as well).
PS -- I see you have Wolfgang Puck Cafe on your list. The almost crusted chicken is insane. This might sound funny, but the restaurant is better than it looks. When you first walk in, it's very packed and something about it seems a little off. But the food was right on.