Pichu hate? What is this forum coming too?
Wait, do you also hate Wobbuffet too, or are you happy to see it?
Crustle is there, so...
That's Ash's, look at the pattern on its head.
No, it doesn't mean they will all be coming back, it's probably just a reference to the past Pokemon that belong, belonged to past traveling friends of Ash.
Anyway, since we sort of have a plot for the movie, I hope this doesn't mean that the location in the teaser trailer will be there in final edit of the movie, but it looks like it might be. Oh well.