'76 V4 Distortion, a couple of questions

[Hangman]

Hmm, is the hum balance pot the original one? I have seen those pots fail and when they do, they behave exactly like you were saying:
"it's quietest at one end of the rotation and picks up some treble noise as I rotate it the other direction."
If you don't have another 100 ohm pot around, try using two resistors as fender did.