I am experiencing the same exact problem! Only one wii remote will work- only player 2, and it does not matter which wii remote is in the player 2 spot (that is how I know that there is nothing wrong with the remotes). Did you ever get this fixed? Any suggestions? Please help, this is maddening!
(I also re-set the sync with all of the wii remotes and system- the 15 second hard re-sync, as instructed by the nintendo support site- still not working!)