you can actuly see bonny when she left or not, it has a shadow on the wall if she's there, and if she left there is no shadow, i recommend put your brightness high to see. Use the alien drawn on the wall for better reference if she is there or not.
Viewing post in (18+) Five Nights at FuzzBoob's: Definitive Edition comments
Now I see it. I also came to conclusion that it doesn't worth to check Freddy at all because she moves 5 times with 85-90 seconds delay starting from Night 3 up to 6th. So Foxy is the only problem but she also has a 14-15 seconds delay if you find Booty cove empty. You can also quick react to her footsteps and close the door right at the moment of her running, not checking additional camera.