They could also have some sort of randomly generated personalities. For example:
So a civilian spawns and randomly gets given a number from 1 to 90. So lets say... 86. They start exploring and they see a person. They have an 86 percent chance of attacking that person with a weapon that they pull out. So the civilian pulls out a pistol and shoots away! If they are killed, it all starts over again!
Soo... in conclusion, the larger the number, the more aggressive that person will be. They will wander around randomly, and depending on their personality number, they will attack people, or stay away. if someone had personality # of 90, they have a 90 percent change that they will attack the first person they see. If any civilian is attacked, they will have a chance of attacking back depending on their personality number. A civilian with a number of 1, will most likely run away if attacked.
Also, the longer a civilian has been alive, the more powerful weapons they will get.
Incorporation with CityRp: They could get jobs depending on their personality, ask to buy weapons (maybe) and get jailed by cops. Getting jailed would lower their personality by 10 or so, and their weapons all get taken away.
If this is at all possible, then I think it would be quite epic.
EDIT: Holy long post...