ok so for 4/20 mode I have sort of a strategy,
When you hear bonnie come to the door i count to 8 using the tempo of the footsteps sound they make, close the door on 8 and open it on 9 and a half and i never even have to use the light to see if she is there or not.
For chica it is a bit different, you still count to the tempo of footsteps, but close the door on 7 and open it on 9, that seems to work better for chica.
For foxy, just count to 3 or 4 then check booty cove and watch for about 3 or 4 seconds and rense and repete. if you see that foxy has left booty cove, the switch to cam 2a to see them run, then shut the left door, because when you see her run she drains less power.
I have not found a solid solution to freddy yet but some other comments suggest when you hear her 5th laugh keep the camera on where she is to prevent her from moving.
even with all of this i still have not completed 4/20 mode, but good luck to you all