I'm on episode 5. So they avoid her to not run into bad luck and stuff... but that means they see her (even though Misaki said they couldn't) so does that mean she's alive? Or is she dead?
Can't post this as a comment, since spoilers. Big spoilers.
No, she is not dead. She's labelled as the classroom's "one that doesn't exist" student in order to make up for the extra, but she isn't the one that's dead. She happens to have the ability to see the one that's dead, and tries to tell Kouichi who it is before being interrupted.