For Halloween the Girl was a Sage, or Shaman. She made the mask with plaster, molding it to her face.
The Boy is a pirate, or a pirate/viking (he has a viking hat, not shown here). With identities obscured to protect the innocent, we have (from left to right) a beauty queen, football player, Bill the Prince of Insufficient Light (from Dilbert), pirate, grim reaper, Sage, Roman centurion or knight, and Oracle.
Blame Montessori education for the weird/awesome costume choices.