With regards to (a), Costco doesn't do that. Their entire Kirkland line is white-label products, excepting their pizzas which use dough made by regionally local

With regards to (a), Costco doesn't do that. Their entire Kirkland line is white-label products, excepting their pizzas which use dough made by regionally locally bakeries. They do have employees oversee (b), but they don't oversee the actual production; they conduct random inspections of shipped products. For example, Kirkland coconut water is simply white-label Vita Coco, and the made by label indicates it is packaged for them by the same company that produces Vita Coco.