2 and 4 are my top picks. 2nd one sounds like an interesting writing excercise and seeing how others explore the material you've provided/made, and 4th sounds neat because I sure do like discussing ideas. Only one I'm a bit iffy on is 3, and when I say iffy, I more mean it makes me think of Kingdom Hearts and how silly that can be at times. Which is great, I love silly things like Cloud telling Sora to "EVOLVE OR DIE."