Godspell is an ensemble show, so the characters are onstage throughout the entire show. Each director has their own particular take on the show, but the original was played with the actors as clowns in an almost comedia dell'arte style. The music is rock and I would suggest auditioning with something from a more rock oriented show. Songs like "I Don't Know How To Love Him" from Jesus Christ Superstar, "Seasons of Love" from Rent, etc
The characters can turn into anything that the actor and director want to imagine them to be. I would suggest approaching characters by song.
Turn Back O Man - Sonia, sexy vamp
Bless the Lord - Joanne, exuberant, energetic
Day by Day - Robin, serious, devoted
Learn Your Lessons Well - Gilmer, comic
By My Side - Peggy, vulnerable
If anyone ever tells you that you put too much Parmesan cheese on your pasta, stop talking to them. You don't need that kind of negativity in your life.