Hi Doc-
Well this has been interesting! I'm not entirely clear on how/why this had the outcome it did- but things appear to be in working order for now..?

After the post from Doc, I hooked up my multimeter and checked fuse #2 again and it showed nothing on either contact. So, like before, I removed the fuse, checked it over and put it back in the slot again. Then I fiddled around a bit- and checked it again and "pop" the fuse blew. I thought that was really weird. So I replaced the fuse with a new one- and now the tail light is working. I will keep an eye on it and see if things change but for right now it appears to be working, and it looks like it might have just been corrosion at the fuse (even though it had been removed and put back in the slot several times, etc.)