What are the roles in Seussical JR. from the most important to the least important?

I am trying out for Mrs. Mayor and hope her role isn't too small because I wanted to try out for Gertrude McFuzz but her role is too big and Mayzie La Bird is my best friend so I don't want to take that from her and Sour Kangaroo just doesn't seem right for me so im trying to find out if her role is small or big or in between..