A metacoin is the same as a user defined coin. There is no difference. You can bet with a user asset versus another user asset.
Anyone (IXC foundation included) can chose to distribute a new asset in any way it pleases. Via burning IXC, by paying a fee, etc.
No, it is not. How many times we need to go through this?
A metacoin is not issued by anyone, it is created within the implementation. Therefore it is not controlled by anyone, and it will exists as long as the protocol exists. Any user definied asset is issued by someone, and requires trust to the issuer (additionally with some legal implications). I could issue a coin mimicin my proposed metacoin 2b), but I can also cancel the coin at any time. I'm sure you can imagine reasons (mob/feds, my family) for doing that.