Generally the person who's car is in motion at the time.
Sounds like Car #1 is at fault
the car backing out.
the car in front of you
The person who drove their car into the parked car.
the other person. he/she should have made sure the rear end was clear before backing. i just seen this same situation a couple days ago.
No. If the accident was your fault, you can not get money from the other person's car insurance.
The car that is moving is the only one with the power to avoid the accident therefore, the other car is at fault. They may say they weren't moving as well though. Good luck.
It would be the car who has driven past, then reversed into you.
The person who is backing out
As far as I understand, if any car is in reverse it is their fault.
Being a guest in someone's house has nothing to do with car insurance. If someone backs into your car then their car insurance is responsible.
Assuming that the car hit was stopped when the other car was backing up, the one backing will be at fault. If there is no damage, or if it is below a certain threshold it may not even count as a collision.