Read in any voice how many times you want! You can audition with any lines you want, or even a demo reel! Existing lines are just examples of some you can say.

Even if you don't fit one of the existing characters, you might still be a great voice actor! You could also be accepted as an extra voice actor or even as a future character who hasn't been made yet! I have a lot of side characters that still need to be made that I will eventually need voice actors for afterall!