When the poster of Babar is first seen, the picture's mouth is closed. when the fork is jabbed into it, the mouth is open. And when the police officer unfurls the poster, the mouth is closed again.
Young Babar: Celeste? You're the kingnapper?
Young Celeste: Yep. This was the only way to save you from Cornelius and Pompadour. And it worked! (turns Young Babar toward a table) French fries for two!
Young Babar: Wow, you did all this just to see me? You must really be hung up on old Babar!
Young Celeste: Hah! What about you? You're the one who planned his own kingnapping just to see me!
Young Babar: Okay, we both like each other the same. Agreed?
Young Celeste: Agreed.
Arthur: What's that for?
Zephir: It's a grappling hook. We'll climb up to Babar's window with this.
Arthur: Why not just climb up there yourself? You're a monkey!
Zephir: Because king-nappers have to do it this way. It's the rules!
Babar: Lunch? That was the extra urgent, top secret business I had to attend to?
Cornelius: Proper nutrition is always a top priority, Babar.
Pompadour: And top secret because we wouldn't want it known that the king of Celesteville still prefers his crusts cut off.
Babar: Good point.
Arthur: Pretty sneaky, sis!
This is a reference to an old commercial for the game Connect 4, where the sister proclaims "I gotchya, diagonally.", and the brother replies "Pretty sneaky, sis."
Young Babar: Go west, young duck.
This is a play on the title of the film Go West, Young Man.