Minecraft is a three-dimensional sandbox game that has no specific goals for the player to accomplish, allowing players a great amount of freedom in choosing how to play the game. However, there is an achievement system. Gameplay by default is first person, but players have the option to play in third person mode.
The Wii Homebrew Applications (such as The Homebrew Channel, Emulators, Games, Media players, etc.), USB Loader GX's NAND emulation feature and DIOS MIOS (Lite) require a FAT32 partition format. You can use a FAT32 SD/SDHC card for that purpose and set your USB hard drive as NTFS or Ext partition format.
If so, then if you want to play with a second person, you would need to buy both another wii mote and a motion plus if the game requires it. If the game doesn't need the motion plus, however, you just need to buy a second wiimote and nunchuck (if the game requires the nunchuck as well). Just to make sure there is no confusion. The wii mote is the actual controller you will be using to play games. The motion plus is just an attachment that connects to the bottom of the wii-mote that allows for better accuracy with it on certain games. The motion plus is not another type of controller, just accessory. The other attachment with a joystick in the middle is the nunchuck.