Most of those have reasons for that, most HP fans aren't as crazy, just go on the forums... >.>
In Twilight when the books were released people didn't like Jacob, maybe like 4% the only reason he's so popular now is because he's "hawt" or "HOT" they might have killed if it went the other, plus it was obvious that she would end up with Edward from the start, or kill him and herself, obsession will do that to you.
Yeah, but not nearly for all the income. We're a smaller percentage of the fanbase. Piss off all the fans and you're in trouble. Piss off all the antis, and not much happens, but you will get a bigger squee fan-base, and they'd probably end up buying more, then, should the anti's have been there.
No. *is speaking from experience of being a ex-squee and current Fangirlologist* Squees are to excitable to do anything that takes that much patience and parents would probably keep their kids at home or in therapy. It will mostly just be crying, mourning, and egging JP.