Here we are. Got some photos.
I wiped away all the mites I found with the cotton swabs and alcohol. I didn't see any webbing. Just the tiny mites in areas. But I can't tell if this is a rust fungus, mite damage, something else? The damage happened fairly quick though.
The spots don't feel fuzzy at all. My q-tips had red residue on them, but I assumed that was the mites I was wiping off. I'd get the red residue running them over the top sides of the leaves as well, where they're still green.
They're both in the same pots they originally came in when I got them around a year ago. I only give them distilled water. They've also been in the same window ever since. It did get sunnier the last few days, but they weren't in direct sun very long, so I don't think they burned. (Also, the undersides were facing away from the window).