So let me get this straight: Hongou didn't volunteer to write the script? What's more, she didn't even have a choice as to the movie's genre?
Maybe this is just me, but it sounds like Hongou didn't have much say at all in this matter to begin with. This is only speculation, but she might have been forced into writing the script one way or another. If you ask me, the heart of this little mystery lies in knowing the actual circumstances behind the creation of the movie. If that's the case, those minutes could be a valuable clue.
As for the movie mystery solving, it was nice to see three entirely different perspectives of looking at "mystery", even if two out of the three hypotheses were massive misinterpretations of the genre. It was interesting to see different takes on what the genre "should be".