Araki didn't forget about the coffin. He deliberately ignored it because he thought it'd be more interesting that way.
The other parts aren't really about a mystery, but Jojolion is. And Yasuho's pretty much the Jobro, except she's Gappy's girlfriend instead, lol. And he doesn't trust anyone else, so.
The other parts aren't really about a mystery, but Jojolion is. And Yasuho's pretty much the Jobro, except she's Gappy's girlfriend instead, lol. And he doesn't trust anyone else, so.