Answer 1

Well, I believe that you don't have to think of something nobody have done before, just think of doing something better, and since you want an android project with database iterations, things like customer handling, tasks to do with suggestions, routines, a new way to save contacts, merging all your favorite social networks in a windows phone way (the only thing that they did better than anyone else in my opinion).

Maybe whatever idea that you may have someone else thought of that and did it first, but again, just do it better, easier, more intuitive and friendly, think of a target audience to your app, and from there you can start small, and grow your app along with your skills and feedback. Good luck man.