Skylar Astin and Rebel wilson had a meeting with the director and they confirmed a Pitch Perfect 2 is being created. Rebel is on board to continue her role as Fat Amy (or Fat Patricia) and I think Skylar is on board as well. They are having talks with Anna Kendrick about reprising her role.
With the rest, they haven't confirmed, but hopefully most of the original cast will be on board. I think some of the main cast such as Adam DeVine (Bumper) won't return because he was a supporting role.I believe a few that were in scenes that didn't make the final cut to the film are going to be main cast in the film. Brittany Snow and Anna Camp haven't been approached yet, but i believe Brittany is willing.
Since they have the same writers, directors and a few others, hopefully it won't turn out the Mean Girls sequel, so the film is in good hands.
Btw love the movie too. I watch it too much.