Good strategy.
Ask to check-in at the Exec Lounge. I've never tried for a check-in that early but you might be lucky. I've also been offered a better suite if I'm willing to wait for one so that might be something you can do if there aren't any available when you arrive.
Regarding late check-out, IME you will be asked at check-in what time you will be checking out at, I've never had a request for a late check-out refused for an evening flight. Latest I've asked for has been 5pm.
Enjoy
