Jack is a young boy. He is bookish, careful and thoughtful, but he is NOT a nerd! Jack has tremendous curiosity about the world around him and loves to take notes about his observations. Jack tends to be very cautious in new situations, and his adventures in the tree house help him develop his confidence. He has a good (and protective) relationship with his younger sister, Annie, though her more impetuous nature often gets on his nerves. This is a big role and requires a strong singer and actor.
Rikki, Baxter, Yates and the Other Castle Kids are the children of the castle servants. They are spunky and adventurous and highly competetive with one another. Consider casting younger or smaller children so they don't appear physically threatening to Jack and Annie. The Castle Kids do not need to sing, so these are good roles for kids who are getting involved in theatre for the first time. Yates should be the strongest actor of the bunch as he is the one who stirs the pot and gets all of the other kids riled up.