Just giving everyone a head's up on the status of this project from hell.
We're done
I took it to the wiring guy at GC today and he wired it up exactly like I showed, sans killswitch. We plugged it into an amp, and bam, hum virtually eliminated. So now I'm confused. I don't THINK I had a ground loop or anything wonky going on, but ok, now I have a professional wiring job for $30. So I go home, wire up the killswitch, take it upstairs, plug in, and the hum is back. Not as bad, but still there. So now I'm very confused.
I decided to A/B the new guitar with my Explorer, in the same position, setup, levels, everything. I laid the V flat down on the ground, face up, with a shirt over the strings for dampening, 3 feet away from the amp. Turned on, starts humming. Turn off, unplug V, plug Explorer, turn on amp. I've got hum. Not as bad, because of the active pickups, but still there.
So the conclusion, and what may have been the issue all along: 1) I'm probably playing too close to the amp, and I have a tendency to face the amp when I play, and my halogen track lights above my desk probably don't help. 2) My amp is just noisy.
So #1 I realize is a stupid, amateurish mistake. One that I'm prone to making to begin with, but ESPECIALLY prone to making when I'm vehement about there being something wrong with the guitar, and ignoring everything else going on around me.
#2 I'm not sure if there's a problem. I just tried it with my noise suppressor and the guitar hum goes away, but there's still some white noise which I'm chalking up to the amp. Maybe a tube is going? I'm not sure what's a symptom of tube ills. But hey, we'll play it as it comes.
Super pumped!