OK I figured it out. Took a while to test everything.
So my board is a
DOL-001 NTSC Revision 1.1 with no SP2 Port. It has all the traces and the through-holes for the plug, but the plug is not there. The plastic housing has a hole in the cast for it, but the aluminum shield does not, so you cannot see the board from the outside.
The issue I had was this: FIL22 (the ferrite bead filter) was not soldered in manufacturing; I assume because it'd be a waste if the port isn't even used. It is on the underside of the board near where the plug would be. The nearby bypass capacitor is also not soldered, but being that we are using a capacitor already, I don't expect this to ever be an issue. So the result was the 3.3v line was broken. Because it's only a bead filter (honestly overkill for the most part and can safely be ignored), I just bridged the filter pads with a little piece of wire to get power to the port. It worked perfectly after that.
Also, I used
ADA254 to hook it up instead of a leftover SD card to microSD card adapter.
If anyone wants to use this in the future, here's some general guidance: the 5v and chip detect (CD) pins can be ignored; The INT (interrupt) line on the gamecube can be ignored (it was never getting used anyway); you don't need two ground lines, only one; when using the 3.3v pin, the built in level shifter is not used, so you don't have to worry about the extra chip on it messing with anything; lastly, it has a bypass capacitor already soldered on, so you can just forget the 22uF cap.
The result is that it really simplifies things in my opinion and I rather like it as it feels more professional. Also, the width of the breakout board happens to be the perfect size to fit in the hole where the broadband adapter would go. So it's a nice little convenient place to mount it with access to the card from the outside.
Hope this info helps others in the future.