So we're going past the Buddha hunt in the story for these movies, which is a relief as I was worried they'd just adapt the first three hunts for the movies.
I dont see many aliens getting screen-time based on these events though. I remember writing a script for the Chibi hunt arc, it went over two tv episodes and when Kurono started to hide, it was about half an hour into the hunt so I intercut him under the tarpaulin with the Chibi searching and the timer going down via time-cuts. Theyd have to do something like this if they get to the Chibi hunt and keep it faithful to the manga (I timed my scripts based on one minute per page (which I double checked to find it did work) to get the hunt timer perfect and faithful for the hunt).
Say we get four hours over the two films, if its mostly action, we'll get less hunts. Getting to the Chibi arc means each hunt has to time a little less than an hour each, so its possible, but there also has to be some kind of conclusion to the second film.
Seeing as we wont see the films until 2011, Im hazarding a guess and saying that the Final Phase will be over before the second film and we'll have a conclusion based around the manga's events. Which may mean we might see Katastrophe for the second film, though I'm not sure. Still, I think all of us want to see the latest arc in moving image right?