This is going to be an all you need to know guide for Five Nights at Freddy's 2!
BonnieBonnie starts moving on Night 2, but is extremely inactive until Night 3. Unlike the first game, he follows a fixed pattern in this game. He starts in the Parts & Service Room, then goes into the Main Hall. Then, he goes to the hallway outside of the office, then enters Party Room 1, then the Left Air Vent. He also bypasses the Left Air Vent's blind spot, so he can catch you by surprise.
He can also immediately move into the Left Air Vent on later nights, and the flashlight also seems to disorient him, making him move slower.
ChicaJust like the other Withered Robots, Chica is active on Night 2, but is inactive until Night 3. She also follows a fixed pattern in this game. She starts in the Parts & Service Room, then Party Room 4, and then Party Room 2, then the Right Air Vent. Like Bonnie, she bypasses the Blind Spot, and only attacks when the monitor is up.
FUN FACT: Withered Chica appears in the Right Air Vent camera just like she does in the East Hall from the first game.