habiku
to answer your first question no it can't. That gets explained in Midnight's Sun. He says he's going to hell because basically he has no soul and he's killed people. He says, "I decided as long as I was going to hell, I might as well do it thoroughly." I'm not sure if that's what you were asking but that's what I think you meant...
Hmmm, really? I thought it just said she ate the pizza he bit into, not actually throughly explain it (the venom).
And the hell question--In NM (yes, chapter stitches), Carlisle tells Bella that Edward doesn't believe there is an afterlife for their kind. Not even a hell. But in Twilight, Edward mockingly states the line (thanks for looking that up), "I decided as long as I was going to hell, I might as well do it thoroughly."
But I might as well be cheating on this question. It was stated in a joking tone, so it was probably just a figure of speech or a loose interpretation of the word.