1 weapon for each member of your mafia with the best offense rating and 1 weapon for each member of your mafia with the best defense rating.
The same applies to armor and vehicles. This will ensure you have the highest rating when attacking and defending as possible based on the number of members in your mafia.
As many as you like. The top 500 weapons will be used though. I have 2000.
There is no real way of knowing this because it keeps changing as Zynga adds new features.
You can only have a maximum of 501 and many people have that.
you can have as many items as you desire. the number of mafia does not affect how many items you may have but the number of mafia helps you in fights and robbing. the more mafia, the stronger you get in fights.
joining a clan or family, or by posting to one of the many different sites that are mafia wars add sites. Depending on where you play, you can just type mafia wars into the search site, and many different things should come up.
At any given point only the no. of Mafia present will be in fight with 1 weapon 1 car and an armor... so make sure you have that and the extra items will add the teams attack and defense.
so far there is no limit on how many family you can have on your mafia family but you can only take 500 mafia families to attack.
3
320
As high as you can practically go
As of now, there is no known limit.
This was a special loot that randomly came up and offered in Mafia wars. Like the gas mask and now they are offering the meat cleaver. The amount of mafia members you have decides how many of these you can get. You can also now get this item by buying a mafia crate.