1) Not necessarily, if the eliminators pulled a WGG or the victim wasn't informed, but that is somewhat unlikely
2) I mean, we know the CoA have to kill all GoH and vice verca, so Joe could be a Child hoping to take out a GoH. It would actually be a better deal than a vig kill in a normal game, since he'd hypothetically have a <50% of hitting an ally. Plus, if Joe had nightblood, he could have attacked knowing it would only kill evil!PK
3) I agree with this. Joe has been one of the most helpful players so far, so I'm hesitant to kill him off out of hand. I also don't particularly like absolutes. It does look suspicious, though
TLDR: Don't make absolutes until we know the specifics or possible extenuating circumstances