Hi Codi,
I find that the restaurants at Walt Disney World are accommodating for children who are picky eaters. One way to ensure that there is something for your child to eat at restaurants you want to go to is to look at the menus. If you go to the unofficial site allears.net, you can click "Dining" and then "The Menus" for a good list of menus.
Specific information on the different
Disney Dining Plans are available online - click the downloadable PDFs on the right-hand side. The Disney Quick Service Dining Plan includes two quick-service meals and one snack per night for each member of your family. The Disney Dining Plan includes one table-service meal, one quick-service meal, and one snack per night for each member of your family. Both plans include a refillable drink mug for each member of the family. The difference between the two is the table-service meal on the Disney Dining Plan. If you think that your family would like to sit down for one meal per day, that would be the way to go. If you would rather grab quick bites, then the Disney Quick Service Dining Plan might be a better option.
Finally, consider putting the money that your family will spend on meals on a Disney Gift Card to use to pay for your meals. I find this to be a good plan for my family as we don't always use up all of the meal and snack credits on a dining plan. This also might help if you get to a restaurant and your child doesn't want to order a child's meal, but rather would have an appetizer or something not on his or her dining plan. You can use the Disney Gift Card and not worry about the meal credit that you are not using. If you have money leftover on the gift card at the end of the vacation, keep it for your next vacation, or use it at your local Disney Store.
Please do not hesitate to ask if you have any further questions, Codi!