Good call on the tiny scratches. I found a small one on top of the PCB after I removed one of the switches. I'm going to try and patch it and see if that works. For the other, I haven't seen anything but it's also mostly obscured by as stabilizer.
As for the heat look, most of that is just flux that brushes right off. for this one, I've soldered and removed it like 5 times so it is starting to look a little jankey, but thanks for the heads up.
EDIT: No good on the solder this time. I'll have to wait for the multi-meter.