Hi Donna:
My family loves both
Jiko and
Boma at the Animal Kingdom Lodge. While the restaurants both feature African-inspired dishes, Jiko is a Signature Dining restaraunt featuring dishes influenced by African, Indian, and Mediterranean cuisine and Boma is a delicious buffet and slightly less upscale than Jiko (though the atmosphere at Boma is still high-quality).
If your family's main concern is that the food may be too spicy, Jiko may be you better bet since you can work with your server and chef to cook your meal to your taste. You may have a little less flexibility cooking food to order with a buffet. However, I've never found the food at Boma to be too spicy, but everyone has different tastes.
Without knowing how sensitive your family is to food that you may consider to be too spicy, it's hard for me to give a recommendation. However, if your husband really likes buffets, you may want to go with Boma and work with your server to recommend items at the buffet that are not spicy.
Enjoy your vacation.