I think this is a great first audition! And I think you did a good job hitting all the important key points! You introduced your characters and gave him a motive to kill Mr. White! You displayed knowledge in how to use masks, too, which is good. We'll see how the results go, but I think you should be proud of what you put together for your first MX Disney audition!
Your plot is so good, and the whole thing is so well paced and plotted. I love how palpable the tension is in that last scene with Ratcliffe,Charles, and Katrina!