The ability to sneak with the secret private eye trait is only available for young adults and older.If a Sim has the good trait and the secret private eye trait, the Sim won't have the option to beat up other Sims for information.Despite the fact that pyromaniac's fire does not harm anything, it will still trigger the fire alarms if there are any nearby, summoning the firefighter and leading to a fine.
If a Sim in a house has already bought the Fireproof Homestead lifetime reward, a pyromaniac Sim will not be able to set a fire on that house.