Prepare the fresh potatoes. If using fresh potatoes, rinse the cut fries and soak them in cold water for 30 minutes. Drain and dry them completely. Skip this step when using frozen fries.
Season the wings. Pat the wings completely dry. Season evenly with the seasoning salt, garlic powder, onion powder, smoked paprika, black pepper, and optional cayenne.
Prepare the coating. Combine the flour and cornstarch in a large bowl or shallow dish. Dredge each wing in the mixture and shake off the excess.
Heat the oil. Add enough frying oil to a deep skillet or Dutch oven for deep frying. Heat it to 350°F.
Fry the wings. Working in batches, carefully lower the wings into the oil. Fry for 10 to 14 minutes, turning occasionally, until deeply golden, crisp, and at least 165°F internally. Larger whole wings may need a few additional minutes.
Drain the wings. Transfer the cooked wings to a wire rack. Allow the oil to return to 350°F before frying the next batch.
Cook the fries. Fry the fresh-cut potatoes at 350°F until tender, golden, and crisp, about 6 to 8 minutes depending on thickness. Cook frozen fries according to the package directions. Drain and season immediately with salt.
Make the mild sauce. Add the ketchup, barbecue sauce, hot sauce, vinegar, brown sugar, mustard, Worcestershire sauce, garlic powder, onion powder, smoked paprika, black pepper, and optional cayenne to a saucepan.
Simmer the sauce. Cook over medium-low heat for 5 to 8 minutes, stirring frequently, until the sugar dissolves and the sauce is smooth. Add water, one tablespoon at a time, if a thinner consistency is desired.
Taste and adjust. Add more vinegar for tang, brown sugar for sweetness, or hot sauce for heat.
Assemble the tray. Spread the hot fries over a serving tray and arrange the crispy wings on top.
Add the sauce. Spoon or drizzle warm mild sauce over the wings and fries, leaving some crispy areas uncovered. Serve immediately with extra sauce on the side.