Don't take this the wrong way, but staying at the airport for twelve hours is an awful waste of time, even if you do have access to the FCL/FCT. If I were you, I'd definitely take a good shower/breakfast at the FCL or Welcome Lounge, and then head out to enjoy the city for a few hours before returning to the airport for the luggage and the FCT experience.
Otherwise, there's nothing wrong with your schedule.