I have understood that Jolla uses Lipstick software to run the home screen (lock screen, switcher, launcher, ...). You probably can customize it. You can use QML to write screens for Lipstick w00t can correct me if I'm wrong
How about the messaging app. Can you open multiple windows of messaging with different people (like we can do on N9)? I keep about 4-5 messaging windows open all the time and I just switch between them on my N9.