That's what I said in my original reply, Tdog. Then Enndoh asserted that they would "ban you for that" (I guess for doing what the title says - having horde and alliance on different accounts), and for that I am certain that he's wrong.

In the absence of existing hard evidence, the general guideline I use is that if I ever feel the need to post here and ask if something's ok, I'd be better off asking a GM directly

There is existing evidence to answer two out of the three questions, and I think there's good grounds for believing that the other is ok too, because - so far as I am aware - Blizz have only ever talked about win trading in arenas and not general "kill trading".

But, yes, that point should certainly be unambiguously clarified with a GM.