Looks like I trashed the Classic II board.

I pulled off solder pads for one capacitor by mistake. Now the audio is completely gone. I had replaced every capacitor near the audio section except for one; if I had replaced the one successfully, audio would probably be working fine now.

The only effect on functionality is that audio is completely dead now, however, since audio was in effect useless before, it is not a huge loss. The Classic II was sold on eBay "as is" and I never stated the audio was working.