Re: Robin or no Robin?
1st movie: No Robin, to give the "new" Batman all the time he needs to be introduced to the audience. Maybe a hint like a "The Graysons" poster in the background.
2nd movie: Dick Grayson is introduced and becomes Robin throughout the movie a lá "The Dark Victoy".
3rd movie: Full mode Robin.
5th or 6th movie: Grayson becomes Nightwing and a new Robin is introduced (Jason Todd or Tim Drake).