As for the QBO....its relevance is still the subject of much debate and their are countless examples, such as last season, when the PV evolves in a manner opposite of what one would assume based on the overall character of the QBO. I mean, we have had like 9/10 of the past winter seasons average a +NAO....I know there were more easterly QBO seasons than that. And as for la nina supporting a +AO/NAO, that relationship becomes much more nebular when the event remains fairly weak, as it should this season for reasons already stated.
What we are then left with is ACE, which is still in progress, and Atlantic SSTs, which at this time are not at all conducive to a negative NAO. How much of that is a "chicken or the egg" dynamic is still up for debate.