Alright, I re-cleaned the board and rinsed it off really well, leaving it to hang and air dry overnight.
Today when I got home from my Lab class, I plugged it in to see what I'd get. The result? What was seemingly no audio output. However, after cranking up my PVM to max I was able to barely hear it, and the same outcome with headphones and the headphone jack.
My guesses at this point are either a dead via, or a dead op amp. I'll be taking it to school with me tomorrow to check it out under the microscope in the electronics lab, and see if that gives me any hints. Any other things I should check for?