The term "picky eater" can mean lots of different things. It would be helpful if you can clarify what you mean: dietary restrictions, vegetarian, alleriges, only likes American food, only likes steak and potato, only likes food cooked/served to order, hates veggies, loves veggies, ...
If you have certian dietary restrictions you can call WDW, the number is right oe the website under dining. You should call at least 48hours before you dine, but Disney is great about accommoating a wide array of needs.