First of all, welcome to WiiChat. Regarding your questions:
1- I know this is game specific, but usually up to how many players can play a games on the same wii console? Can different moniters be used for shooting games, or do we have to split 1 moniter?
A maximum of 4 players can play a game on the Wii console in multi-player mode. The screen is split into two or four different segments to allow each player to interact with the game and each other. I am not sure if more than one screen can be used.
2- Is there any way to network 2 or more wii's? (without going on the internet)
As far as I know, the answer to that question is "No".
3- How often does your wii break down on you?
My Wii console has never "broken" down on me at all.