The Intermezzo may be for tone quality, expression in simple passages. The list is very similar to those used by the Metropolitan Opera and the San Francisco Opera. As for preparing, not only must one know all of this thoroughly, you should be prepared to sight-read anything in the rest of those operas, and the entire opera literature as my teacher used to say. Opera is rather a specialty, as is ballet as well. At least they didn’t ask for Wozzeck.