Nutrition information is based off of low carb tortillas, each being 80 calories per tortilla with 7g of fiber. You can use regular whole wheat tortillas as well, just know that the calorie count/nutrition might differentiate.
To make gluten free: Use corn tortillas instead. You may need to layer them a bit and use a few more since corn tortillas are typically much smaller. Check out this recipe as an example of how to layer them.
Feel free to use whatever vegetables you have on hand, this is great for mixing and matching. Corn would be delicious as well as any seasonal squash during the winter months.