Im starting to work on the first post now, for your first post start it off as a dream(where your dive of heart occurs). I encourage you to make your dive unique. It can occur however you please but try keep it along similar lines to Sora's and Roxas'.
Im also looking to kick start this a little bit, so when your character wakes up the heartless are beginning their attack. Do as you please from here, run or try to fight your choice, I'll run into you one by one or you can run into me. Upon seeing my keyblade you connect the dots and your own keyblade appears.

EDIT: IC POST FINISHED alkfhuavlkhfnkasf