The menu changes daily in the main dining room.
What extra charges?
You CAN request and get assigned seating. And you can request and get the same waiter, etc. if you wish.
You can sit with your friends at the same table every night if you wish.
Tips are prepaid UNLESS you don't wish them to be. "Freestyle" means it is your choice.
And, finally, why are you so negative about everything NCL. Have you ever cruised on NCL?