Howzabout we do a reverse I'm Not There and have one actor play every single character in the movie.
Also I don't think the character should be called Plunko but I'm very excited at the concept of having the movie title first and working everything else out later.
Maybe Plunko could be the starfish's name or a bands name.
Here's an idea. Forget the sex change, she's a quirky, creative yet unpopular individual, due to a clerical error she gets sent to a special ed school. She doesn't say anything about it to her elderly grandparents (who she naturally lives with) and nobody at the school notices. At first she's happy to be doing finger painting instead of normal lessons but soon starts to shake things up and serves as a catalyst for the entire student population to start doing crazy things - starting punk rock bands, painting huge guerrilla graffiti murals at midnight, making their own clothes etc.
Eventually the exasperated school administration discovers she is not supposed to be there and she is forced back to a normal school but she has changed the lives of all she met at the special ed school forever.