The good news is that I've found the font files. There's 8 of them (2 for english, 2 for each kana, and 2 for kanji). The bad news is that I can't figure out the image format.
I've managed to extract one image: http://i.imgur.com/2YDnx4x.png
That particular image has a color table, followed by each pixel referencing a certain color. However, other images that seemingly use the same format, come out somewhat recognizable, but are clearly wrong: http://i.imgur.com/JwYSvlK.png
And worse, there are some images (like the font tables!) that seem to not follow this format, and instead do something else.
Instead of going to the color table (of RGBA format, with an indicator for how many colors), it goes to something that looks like this:
F7 F0 F0 F0 F0 F0 F0 F0 F0 F6 F0 F0 F0 F0 F0 F0 F0 F0 82 F0 82 00 F7 F0 F0 F0 F0 F0 F0 F0 F0 F6 F0 F0 F0 F0
It's F0's all the way down pretty much. I thought that it might simply be the RGBA (or some variant) format, just without a color table, so I tried that and this was the result: http://i.imgur.com/cvBGxdb.png
Note, it's not just all F0-FF (which I thought it might be). As another section of the image looks like this:
0F A5 83 F0 08 0F 2D 5A 78 78 96 2D 0F B4 82 F0 09 78 0F 0F 1E 5A A5 B4 96 78 E1 F7
Clearly there's problems. There's no discernible palette file for these either. Any thoughts? Am I forgetting something about image formats that may be helpful here?
"I heard Nintendo Puzzle Collection was one of the games to use the BIOS font (which is suggested by videos I've seen with mostly glitched text, likely as a result of being played on on a western console.)"
As far as Panel De Pon goes, the font is included in the "MENU.BIN" file. The game runs fine on my US Wii (through USB launcher). I can't say for the other two included games.
"and may actually really just be a solid square (■, for example). "
Haha, though it's not actually just a square. This is actually what I was referring to: http://i.imgur.com/2MCQsSb.png
. That screenshot is actually a bit clearer than when I was looking at it (it moves around too). I'd imagine if you were familiar with the language, it's easy to know which it is. But honestly, I can't tell where the lines are, and it just looks like a big blob with an L next to it.