This managed to connect four of the other stories by my count. I was wondering if the universe in here might be linked. On that note, the first chapter had the protagonist judged by her cat, and the aliens from Handspinners were cats. And that one ALSO mentioned the comet Melancholia... And it's implied the cat in the first story had the ability to send the MC back in time.
Basically, all of these really ARE in the same universe. The cat aliens are the cause of the apocalypse.