That doesn't seem especially profitable nor a core competency of AMZN. When you see a store branded bottle of ibuprofen, it's just a re-label of their contract manufacturer's pills.
Yep. The AmazonBasics brand of aspirin may appear, but it will just be putting their label on the product manufactured by the companies already specialized to manufacture it (as is probably true with a lot of existing AmazonBasics products).