Clare_N
And, when it comes to elemental powers, you must assign powers based on the characters' genders. To put it simply, only boys are allowed to have "earth" or "fire" powers, while the powers of "wind" and "water" must go to the girls. That is, unless you have an all-male or all-female group.
But you can give a girl "earth" powers if "earth" = plants and animals. This is because making pretty flowers grow and charming songbirds and other cute forest animals are female powers. If the "earth" powers involve shaping stone magically or hurling boulders at someone with your mind, though, it'll be a guy.
In the event that you have a female earth character, the wind character must be male. This is because you can never have a male water character (because water = healing and healing = female, remember?), and if it's a mixed-gender group, the girls cannot outnumber the guys.