I've meandered through a few weeks of low activity, but I finally had time to track down the bugs that arose when I tested out my most recent PCB revision. 

First bug was the power switch MOSFETs that didn't seem to work as expected. 

That turned out to simply be caused by a coding error. When I shuffled around the GPIO pins there was a stray line of code left that gave rise to some hard to diagnose problems.

The second bug was specific to the Adafruit HUZZAH32 dev-board. Two of the hall switches didn't trigger as expected like they would when using the TinyPICO dev-board.  

This was due to me not reading the datasheet closely enough. To save on external components I use the ESP32 internal GPIO pull-ups to hold the output of the hall switches high. But it just so happened that those two particular GPIO pins didn't have any pull-ups. That was a face-palm for sure. Actually both of these issues were very avoidable.

No matter. I've updated the pcb design and sent it off to fabrication today. Expect to get the boards end of next week.

In the meantime there are plenty of loose ends to tie up in other areas of the project.