Great story! I appreciate the measurements.
I tried using PF5102s in the one I'm fixing and they both saturated. When Vd & Vs are the same voltage, you know it's not gonna work! In your pedal, Q1 is near cutoff, so Vp is not far from -0.19V. Q2 is near saturation, but its Vp must also be pretty close to -0.2V. JFETs are pretty stable over time and temperature, so one or both of the JFETs in the one you sold must be right on the edge of working / not working. One alternative to hand-picking JFETs is to make the drain resistors select-in-test. I'm trying to avoid that with the one I'm working on because I want to nail the original sound. I'd be interested to know if every Unpleasant Surprise that Fairfield builds has the same drain resistors. At the very least, they're cherry-picking JFETs.
Thanks again and enjoy your weekend off!