1) It's possible but highly improbable, even if it does happen it likely won't be fore more then a week.
2) I doubt it... If so, it'll be based soley on the fact that the japanese don't buy a lot of software. DW5 really underperformed. The Japanese may be finally sick of their Chinese history. Or just their DW games in general. See Gundam Musou.
3) Seems... extremely unlikely... I mean the game is stronger in the US... and it's US sales have been a huge disapointment.