The alignment tweaking seemed to have a much greater effect than did the bushing lubrication; they were done a couple days apart. What does that tell us?

As for the tires, in the midst of all this I've replaced wheels/tires and it didn't seem to change anything. I am going to get the tires rotated and get everything balanced (hopefully this afternoon) and see if anything improves.

I had a feeling the rotors/discs were a problem. However, should it vibrate every time I brake? It doesn't, which makes me a bit suspicious.