OK, guys, I tried the Phillips screwdriver thing on the bolt sticking out of the FD clamp.
I tried it left handed, I tried it right handed. I cannot get it to turn either way.
I tried a small Philips, I tried a medium Philips. It's soaking in WD40, but it's not rusty or corroded in any way.

There is a very thin ring around the bolt, tight up against the ring, which has the two overlapping ends that the bolt goes through.
It appears this ring is so tight, it's not allowing the bolt to turn at all.

I've thought about sawing off the seat tube above and below, but that would tend to jam me up on the rebuild.

I'm going to try again tonight, and then try some Yuengling.