Is it better if a director calls you back for one part? Or many parts?

Whenever a dirctor calls you back that means they believe you are right for the show, so they need to cast you. Usually when you walk in they already have a character in mind that you would most likely be cast as, and that may or may not be the character you read for at the call back. A call back does not guarantee you a part, actually. It is a chance for the director to envision different students in each role and who works well with others. If you got got a call back for Serena, the director can really see you fitting that role. It's neither good nor bad, it's just how theatre works. And you got cast as Irene because you were the most impressive, obviously! There's also this scenario: you read for Serena, but you could be cast as Grace because you may look sweet and innocent but have more to offer as the "bad girl" type. I would know. I'm branded an ingenue for life because I am a blonde-haired, green-eyed, fair-skinned soprano. That bites, but maybe I'd love to play Roxie Hart someday...and I always surprise people. Call backs are nothing to stress over. If you make it past Round 1, great; you get to show off more to the director, but they could always change their mind. I got a lead in a play two years ago...no call back! It was a wonderful experience. Break a leg!