Okay. So, I went ahead and just filled in the beginning of the intro school scene. 

Scoobies got to school, and huddled in a private study room in the library to discuss the crazy thing that occurred the night before. So let them talk, let them recount, let them guess, or let them debate. When I feel it's time, I'll have Emy and the Librarian walk in.

Then fireworks can start. In the meantime...everything from the night before, to that morning, to when they end up in the study room and start talking is entirely your domain. Enjoy. 

Anything I can do to assist/help, just let me know.