Cook sausages in a skillet over medium-high heat until browned and heated through, 7 to 10 minutes. Remove from heat and cut sausages into bite-size pieces.
Melt margarine in a large skillet over medium heat. Cook and stir onion and celery in margarine until softened, 7 to 10 minutes. Transfer skillet contents to a large bowl.
Stir sausage and apples into onion mixture. Add cornbread stuffing mix, seasoned stuffing mix, poultry seasoning, salt, and black pepper; mix well. Stir chicken broth and eggs into stuffing mixture; pour mixture into a 3-quart baking dish and cover dish with aluminum foil.
Bake in the preheated oven for 20 minutes. Remove aluminum foil from dish and continue baking until browned and crisp on top, 10 to 15 minutes.