It works now! I fixed it! Not sure which step cured it, but...
I did all of the above.
I removed the bobbin case and assembly, cleaned all carefully (used a pin to reach into slits and crevices).
Used a magnet on a stick to check the inside of the bobbin area. Shook the machine upside down. Used a vacuum cleaner to suction fuzz out.
Changed the bobbin and the needle.
Voila! It works again. I know that I'm very lucky that I didn't damage the bobbin case or assembly breaking the needle.
I also can't help but think that having a quality Baby Lock machine could be the difference. I'm not sure my bargain Janome would come out the same.