In a sense, it's not that relevant. People are not in the market for an lg and decide to get one of these. People are in the market for a €300+ phone and pick one. I doubt this will cannibalise LG any more than it does any other high end android/phone manufacturers.
That said, if these were being pushed in stores today, I imagine they would be picking up a nice amount of the Christmas trade. Especially since an unlocked phone makes a nicer gift.
Well, yes, but if LG is at production capacity (unknown, but it's possible) it's pretty easy to see which channel it will fill first. The question isn't which one will sell more overall, it's given an existing quantity of product which orders will you fill first.