No tour I'm aware of - and tbh most things will be closed. Personally I'd just get a hotel near the airport and crash out. Even with hand luggage, you're not looking at arriving into the city centre until 11.20 or so, and having to get to the airport for about 8am.
As for pre-clearance I'd be there approximately 75-60 minutes minimum or so before the flight. There are a couple of US bound flights at that time pre-clearing so it can be a crapshoot. You may breeze through, you may be held up for a while.