Other mistake: When Aang is reading the letter from The Guru, as Sokka says, "What's a guru? Some kind of poisonous blowfish?" his right eye loses its white colour three times during the shot. (00:18:19)
Other mistake: When the group goes to hug Sokka before he and Aang go to Chameleon Bay, you can briefly see that Toph is incorrectly drawn with arrow tattoos on her hands, like Aang has. This happens very fast, but you can still catch it when watching the episode normally without pausing or slowing it down. (00:20:35)
Answer: The pirates are from the episodes "The Waterbending Scroll" and "The Waterbending Master" (They're the ones Katara stole the scroll from). The traveling musicians are from "The Cave of Two Lovers. The prisoners of war likely refer to the Kyoshi Warriors, the men of the Southern Water Tribe, and possibly Bumi and the other citizens of Omashu.