Well, I'm actually still in the process of reading it, but I had some thoughts about the first bit.
Spoiler for Mesomeso-san, minor Umineko spoilers I guess?:
I wonder if anyone else had an experience like this... The two incidents that spawned the Mesomeso-san legend somehow reminded me of Umineko, so that I started thinking that there could be a hidden non-fantasy side to Kanamori's disappearance. In the first place, what happened to his body? The rumors afterward made it sound like he just vanished without a trace. Did any of the teachers notice that he'd locked the door of the old school building in the morning? And so on. Actually, I started suspecting the nurse a bit after the button incident as well.
Well, I'm probably just overthinking a pure fantasy story. But on the other hand, I think it would be interesting if Ryuukishi took the fantasy/reality worldview of Umineko and turned it backwards, so that the fantasy took center stage and controlled what happened in reality.
Guess I'll see whether that idea gets jossed in the next chapter.
