If any egg is on the paint get it off PRONTO! Between the eggshell and the egg itself it'll eat the sh*t out of your paint.
Report to the police and offer a reward for info. Maybe one of the kids will feel guilty and turn in the perp.
Here in Sherman we have a rash of car break-ins. Thieves take wallets, phones, lap tops. Not sure what people are thinking leaving that stuff in the car. Also a lot of the time the car is not even locked, not that that would stop a determined thief.