I am in need of some homework help, please-

I am having a hard time identifying both the mens rea and actus reus for accomplice and accessory liability on the case facts below. I need to consider how party-to-a-crime liability (accomplice and accessory) is different than vicarious liability and answer the question after the facts are given. Thanks for your help in advance.

Facts:

Roy (16) and Johnny (20) were friends.They stayed up all night at Roy's house watching aCSImarathon on the local cable station.When Roy's mom roused them in the morning, the guys joked about how easy it would be to rob a convenience store.After Roy's mom left for work, Roy and Johnny went over to a neighbor, Dixie, and asked to borrow her car.When Dixie asked what they wanted it for, Roy said, "to rob a store, what else?"Dixie laughed and then offered to make Roy and Johnny a pancake breakfast.She said, "you boys are going to need your strength."As Dixie manned the griddle, Roy and Johnny boasted about how they would never get caught like the fools onCSI.At one point, Dixie chimed in, "you guys are crazy, but if you really need my car, here are the keys."Roy and Johnny downed their pancakes, grabbed her keys, and left. Soon, Dixie started to worry.She called the police and told them that Roy and Johnny were going to rob a store.She described her car, but Dixie did not know the name of the intended store.

In route to the store, Johnny gave Roy his loaded .357 revolver for use "just in case." Once they arrived, Johnny waited in the car while Roy entered the Quik Trip.Roy pointed the gun at the clerk's head and demanded all the money in the register ($500).He also pointed a gun at a customer and robbed him of $200.As Roy was leaving the store, he shot and killed a police officer who had responded to the store's silent alarm.

Roy and Johnny first drove to the Rampart Hospital Emergency Room where Dixie worked.They gave her a plastic bag with all the money in it and asked her to bring it home with her after work.She asked them where they got it, but they told her it was from the casino."You guys are crazy," said Dixie.She then promised to bring it home later that night after she got off work.Johnny and Roy then drove around the rest of the day until Dixie got off work.Then they drove back to Dixie's house to return her keys.She gave them some bottled water and told them to leave out the back door.When they did, the police were there and apprehended them.Roy was charged as an adult.The prosecutor also plansto go afterJohnny,Dixie, and Roy's mom.She wants to charge those threewith the following crimes:

1. Robbery of theteller
2. Robbery of the customer
3. Murder of the police officer
4. Accessory to robbery
5. Accessory to murder

I am the prosecuter:

The question is:Under what theories of liability will you proceed against Johnny, Roy's Mom, and Dixie?Do not discuss Roy.What will be the likely outcome at trial?

I need to consider the elements of the following statutory references in Arizona:

-A.R.S. 13-1104 Second degree murder- without premeditation, (1) The person intentionally causes the death of another person; (2) Knowing that the person's conduct will cause death or serious physical injury, the person causes the death of another person; or (3) Under circumstances manifesting extreme indifference to human life, the person recklessly engages in conduct that creates a grave risk of death and thereby causes the death of another person.

-A.R.S. 13-1902 Robbery- A person commits robbery if in the course of taking any property of another from his person or immediate presence and against his will, such person threatens or uses force against any person with intent either to coerce surrender of property or to prevent resistance to such person taking or retaining property.