So I think of the countless times that I hooked the Wiikey Fusion up to the gamecube improperly, I damaged it.
I tested the Wiikey Fusion on my Wii. Interestingly, the controller doesn't work in the Wiikey Menu, but after pressing the reset button on the wii a few times to select a game, I can select the game with the controller. To restate, I can't use the analog to select a game, but after pressing the reset button on the wii to select the game, the controller works. The controller works in-game as well!!! I have no such luck with the gamecube. Therefore, I think the Wiikey Fusion is damaged (because I still get a slight malfunction on the Wii), and I bought a replacement.
So while I'm waiting on my replacement Wiikey Fusion, I decided to make a Wii Portable as a side project:
Then, I decided to see if the Wii could fit in the case I purchased earlier. It fits!
As you can see, I removed one of the gamecube memory card ports and the sensor bar port in order to slim everything down.
I also removed some of the fins on the heatsink in order to make room for the screen.
I will need to trim the motherboard's outlining ground opposite the gamecube controller ports in order to better fit everything in the case.
Anyways. My new Wiikey Fusion will arrive tomorrow. Hopefully, I can simply hook it up into the gamecube motherboard I already prepared. If I STILL can't get the controller working in-game, I'll use the gamecube DOL-001 (shown in the image above) I purchased off ebay for $20.