Right now, I have finished probably around 1/3 of the animation, but I can't really predict how long the full thing will be. We are thinking around 10 minutes, however it could be totally different.
Since school starts next week, I probably won't have as much time to work on it as I do now, so maybe I'll do an animation grinding session (or a few) before summer is over. We have no set due date, but I'm thinking it will be sometime in September.
Also, here is the preview screenshot I promised! :D