This is a tough situation. Your only chance could be the existence of the third party witness that says the person coming down the aisle was traveling at an excessive speed. It is also just as likely that both insurance companies will decide that both parties are equally At Fault and let each take care of their own damage.
You are at fault.
Any time the driver who is backing is at fault, in all 50 states.
Backing up--it is your fault.
Well if you were backing in and hit someone then it is your fault. But if they hit you, then it is their fault.
If you strike him - you are at fault. He can be charged with the No Parking violation but YOU are charged with the collision.
both of you for not looking back
The guy that is walking.
In most circumstances, the backing vehicle has the greater duty of care and would be found at fault.
If you are driving the backing car, no matter WHERE the other cas is located, YOU are the one at fault if you collide with it.
The greater fault lies with the person backing out of the parking space. You may still be partially at fault for not driving with due care.
The person backing out. If you were in the lane/road behind them they needed to use caution when backing out.
Most defintley his fault, you were backing out, he should have saw you first.