Taco Bell's allergen tool identifies egg in some menu builds, including the standard Chicken Quesadilla. Because that quesadilla includes Creamy Jalapeño Sauce, chicken, cheese, and a flour tortilla, you'll want to check sauces and every other component instead of judging an order by its main filling.
Many Taco Bell standards include obvious milk ingredients, but removing cheese isn't the whole milk-allergy review. The Bean Burrito includes cheddar cheese, while the Chicken Quesadilla includes a three-cheese blend and Creamy Jalapeño Sauce. You'll want to check every retained sauce and topping in the customized build.
Soy at Taco Bell isn't limited to an ingredient named soy on the menu. The official allergen tool identifies soy for standard builds such as the Bean Burrito and Chicken Quesadilla, which combine tortillas, fillings, sauces, and cheese. Review the allergen result for your exact build component by component.
Flour tortillas make wheat a direct concern in many Taco Bell burritos and quesadillas. The standard Bean Burrito and Chicken Quesadilla both use flour tortillas and are identified for wheat in Taco Bell's allergen tool. If you're considering a crunchy-shell swap, check the new shell and the entire changed build rather than stopping at the swap.