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.
You can't add files larger than 4GB to a Fat32 formatted drive anyways...so unless all of your backups are <4GB NTFS is your best option. If you wanna use emulators put a new 32GB partition in front of the NTFS partition and format it to Fat32 with 32kb clusters. Make sure the new Fat32 partition is the primary drive and is physically in front of the NTFS partition if you plan on using a GC emulator.