Newtype is going to have a feature on the Star Driver movie this month. They'll have comments from the staff and cast, etc. So I guess they announced this just before anything would leak from the mag. Pretty smart!
Confirmed returning characters from the official site: Takuto, Sugata, Wako, Head, Fish Girl, Keito, Benio, Kanako, Midori, Mizuno, Marino, Serina, Ryousuke.
Edit: The TV site has a full visual (lower resolution though) which shows the extra parts of the artwork at the top and bottom too: