Hi Matt,
Yes it is a kind of reiteration on the circuit in the first post. Most of my understanding and concept of this type switching came from "Mictester "over on the Freestomboxes forum, there's a great thread there that details a lot on this type switching and various ways to achieve the end result , see the link -
https://www.freestompboxes.org/viewtopic.php?t=31684&sid=cfa1ec3ce2be598ad191301a0ed79cbeOnly there was never a way to reduce the inadvertent switching clicks, thwacks and the like. So I utilized the concept of the temporary mute type arrangement where one temp mute circuit activates on switch in and the other on switch out, which is same ideally as how its done with an MCU microprocessor and also in various other audio equipment to keep out the unwanted switch clicks. If you want to test the efficiency of the temp mute, just add in a resistor from the Mosfet drain to an LED Cathode, with LED Anode to a positive voltage, this will give an indication on the time span of the temp mute and show it working adequately, it is pretty effective in reducing the switch noise issues.
And yes it is IC1B pin 4 of the 40106 that activates one side of the temp mute circuit either in or out, depending upon whether you are using the Bypass @ startup or the FX on at Startup circuit, they both differ in opposite ways where the mute function works,
The second side of the temp mute circuit comes off the Relay Positive input, where the charge into the 220uF Electrolytic allows a short pulse that activates the mosfet open to allow temporary GND to the Guitar Output Signal.
As for the way the circuit works it has an active "High Reset" circuit in components D4 and C4, which force the first stage schmitt trigger to always start up in High positive output, which is held in place, the second stage at pin 4 starts up in a low state GND, 0V. Then when the momentary switch is pressed the first stage goes low and the second stage goes high, always being held at the voltage accordingly.
Put it on a breadboard and see how it works, its a reasonable alternative to the Microprocessor pathway to True Bypass Relay Switching with a mute function. And there aren't a whole lot more components, especially if you end up shrinking them all down via SMD components, the circuit almost fits on a postage stamp.