Moscow is only available on Facebook because Facebook was authorized by Zinga to release Moscow.
try joining the pimping services. there are a lot out there. they will boost your mafia family in hours.
You can hide it by not making a top mafia or it may not appear because there is always a problem with top mafia even showing up.
You cannot join the Mafia. The Mafia will come to you in person if they need your assistance in committing crimes.
Typically, to be initiated into the Mafia, one must be a member of a trusted family or much like any other gang association, undergo some sort of initiation.