Have to wonder what's so bad, that death is preferable. Alternatively, Hanamaki's suicide attempts upon reading the book may end up setting that event into motion. There's a decent chance she gave herself brain damage from the lack of oxygen.
As for Chacha, I think it's the same Chacha physically. But coming into contact with Gray stuff can change a person. Yagi better be careful, especially since I'm pretty sure Chacha was investigating Yume's adopted parents, not her biological. With Yume's senses, she's probably got Gray in her blood.