I would like to add a fourth designation: what the rules recommend. And I would like it to be given some weight, because even when it isn't outright forbidding or allowing a particular thing, it is still in the book and intended to inform how the game is played.
I agree with this. An understanding of the rules shouldn't be only about whether something is explicitly forbidden or explicitly allowed. There are several parts of the rulebook that read along the lines of, "Well, technically you can do that, but..." which should be given attention as well.
Yes, when playing the game, the RAW is what should be followed above what happens in the novels, with the caveat that what's happening is covered by the RAW. I would say that, in the case where a situation that arises which is not covered by the RAW, but is handled in the novels, what happens in the novels should have some weight, even if only as a consideration.