Hi Amy,
I'm happy to help further!
Pepper Market is a great choice when on the Disney Dining Plan because it's an excellent value for a counter-service credit. Still, it's a wonderful place to eat without the DDP too. My family always pays out of pocket for our meals and we've enjoyed some great meals at the Pepper Market. Yet, it's not as convenient as the food courts at the other two resorts that you have mentioned.
Given that you have older children, I would scratch off Port Orleans French Quarter. While the resort is charming, the pool slide is for small children. Since you are looking at food courts, Sassagoula Floatworks and Food Factory is much smaller than the food court at Port Orleans Riverside. Traveling with older kids and picky eaters, opt for Port Orleans Riverside over French Quarter. The pool is great for kids, has a fun slide, and the food court,
Riverside Mill, offers more variety.
If you'll be having a lot of your meals at the resort, and the eats at Cafe Rix won't do the trick, then Port Orleans Riverside would work best. It's a beautiful resort!
I would go to www.AllEars.Net and check out the resort menus. This will help you choose the resort that is best for your family. Take a glance at the menus, then if you have further questions, just let me know. I want to be sure that you are selecting the resort that best meets the needs of YOUR family.
Wishing you a magical vacation!