Big, big error — June disappeared, it is May who is dead. We learn very late in the book via Jenny's year-later second reading between lines of Ann's "regret to inform you" letter, May is buried next to Wade's father, where Wade has also been laid to rest.
It took me awhile to get into this book, but it grabbed…

Red tag probably refers to the identification tag clipped on every handmaid's ear. In episode 1 they showed it when Offred was sinking into the bathtub water. If you haven't seen tags on livestock before, you might have mistaken it for an odd type of earring. It was clipped to the top of her left ear, and is red.