The guy who plays Goyle leaked the details. It was all over the Harry Potter fansites, the directors and what not confirmed it but they detto it could change between now and the time the movie comes out. But as of now that's what they are going with.
That's lame, the Malfoy Manor scene should NOT be at the beginning of a movie. It's going to be too emotional for the beginning. I think they should end the first movie AFTER the Malfoy Manor scene.
I believe it's still unknown, although there was speculation at one point for the scene with the snatchers. I think though, they hadn't decided, o hadn't released the information publicly.