I've worked on a lot of these, and those don't look like any screws out of that model. I'd be willing to bet they just ended up in your screw pile from something else.
A RAR file is an archive format. You'll need to extract it using a program like 7-zip or WinRAR, and then you'll end up with a folder with all the case files in it.
I’ve built 2 Wii portables so far, however neither of them were of my own design. I hope to change that with this project. My overall goal for the 3-Wii is to build a highly compact, fully featured, and practical Wii portable. I have some more specific objectives that that, so here they are...
Just gonna throw this out there. You really shouldn't sell your first portable, it's a bad idea for a multitude of reasons. There's a lot of weird stuff and tricks to figure out with assembly, your first attempt is really a learning experience and might have some issues that pop up down the...
The G-Boy controller PCB is a custom adaptation of the GC+ 2.0, which is an open source GameCube controller emulator made by Aurelio. You can check out the code here: https://github.com/Aurelio92/GCPlus-2.0. You can also buy an assembled, general purpose version of the board from 4Layer Tech.