Heat the oven to 400°F. Line a rimmed baking sheet with parchment paper or foil.
Cut the potatoes lengthwise into wedges. Toss them with olive oil, garlic powder, paprika, salt, and black pepper. Arrange the wedges on one side of the baking sheet in a single layer.
In a large bowl, combine the ground turkey, stuffing mix, egg, milk, 1/4 cup of the barbecue sauce, and 1/2 cup of the cheddar. Mix gently until evenly combined.
Shape the turkey mixture into a compact loaf on the open side of the baking sheet. Leave a little space between the loaf and the potato wedges so they roast evenly.
Bake for 25 minutes. Remove the pan from the oven and spread the remaining 1/4 cup barbecue sauce over the meatloaf. Sprinkle the remaining 1/2 cup cheddar on top.
Return the pan to the oven and bake for 15 to 20 minutes more, until the meatloaf reaches 165°F in the center and the potato wedges are tender and browned. Let the meatloaf rest for 5 minutes before slicing, then serve with the wedges.