Well since no one answered the questions yet. ( I can only answer a few due to me not owning a wii yet)
1) I believe a 1G should do.
2) The kind you find at Canadian tire
3) Well i dont need to worry about that cause i dont have the money for the Wii but for you I say just get.
5) I went to the GameStop website. That didnt help me much. But LOL Wii's you cannot order online cause their out but you can still order ps3's . Hmm I wasnt much help there was is . Well I Tried.