If you don't know what the mafia is maybe it's best to stay out of this thread
I would go for Uncle Tom (Nook), Cousin Anchovy and Cousin Blathers. Blathers is always so tired during the day, not because he's an owl, but because he's up to no good at night. Tom Nook - where does he get his money for his store upgrades from? He can't get it all from mortgages, and no villagers ever came to his shop (at least not that I know of), he forces you to work for him, pays you very little, has mysterious packages for you to send... and Anchovy, well, why not?