While this thread is an old one, I'll write down the core mechanics of the girls here as I understood them during my road to doing max difficulty Custom Night, for anyone else coming by.
Milkamean (the pink-haired burger girl): Always approaches the left door on a varying pace, always appearing on Cam B before the doorway. Most of the time her arrival at the door is indicated by her ghastly companion, Pink Fury, sliding across the screen. Repel the ghost quickly to avoid distraction and power drain by repeatedly flashing the light in any direction, and shut the door on Meanie until she hits it.
Miss Suki (the batty inflation teacher): Mostly similar to Meanie, approaching the right door via Cam A instead. Her closing in is harder to notice due to lack of a companion, so just keep a closer watch on the right door.
Paranoia (lady watching television/eldritch horror): Watches the television in Cam 5. Behaves very similarly to Puppet in FNAF 2: simply hold down the rewind button on her camera view any safe chance you get. If the meter runs out and she disappears, you're finished.
Sandy (jumpy mouse girl): Partially similar to Foxy in FNAF; starts off calm in Cam 9, over time eventually gets up and stares at the camera. After staring at the camera for a while, she loudly runs towards the left door, ending your watch if the door isn't closed at the end of her steps. After being blocked, she struts through Cams B,1 and A to your right door. There, she will quietly peek in at which point the door needs to be closed as per usual. After hitting the right door, she returns to Cam 9, starting the cycle again.
Crystal (obsessed orangette) and Elina (dark-furred ghostly... something) (separate characters but work mostly similarly): Both will attempt to get through the vents from Cam 7 to Cam 10. Disappearing from Cam 10, they peek into your office through the middle doorway, where they must be scared off by rapidly flashing the light at them. While Crystal causes a Game Over upon slipping through, Elina will send ghostly hands to attack you instead. If you stay still for long enough (Flashlight and clicking a button is still allowed), the attack will fail and Elina will retreat.
As a final note, unlike the Five Nights with Fatties sequel, running out of power does not cause an isolated sequence before you lose. Instead, the game will simply progress with doors permanently open and cameras unaccessible, until you get attacked by whoever happens to get there first, or until you get lucky and reach 6am.
