Cook the meatballs according to the recipe directions. Meanwhile, prepare the sweet potato fries according to the package directions.
Toss the cabbage and scallions with the mayonnaise, cider vinegar, and celery seed; season with ¼ teaspoon each salt and pepper.
Toss the meatballs with the barbecue sauce. Dividing evenly, top the rolls with the meatballs and slaw. Serve with the fries.