- You can update the d2x cIOSes directly, latest I know it's v10 now.
- You won't need any other cIOS.
- You can update USB Loader GX directly and nothing should break, unless you used a very old version. Though it's not a very difficult thing to solve, usually by using default configurations.
- DIOS MIOS is now obsolete, use
Nintendont instead to play Gamecube games.
-
Nintendont is the latest and coolest thing that happened in a while.
- And finally, using
Nintendont will let you use any controllers, including Wiimote+Nunchuck, classic controller, WiiU Pro Controller and many HID compatible controllers via USB.
I hope that helps.