Basically you got it the way it was always intended to be
About being stuck at the gas station, there's a good chance setting it to sensorless would have gotten you home. On the flat with little load it will start from standstill, on my bike I can ride away sensorless under power with no help pedalling. Even the tinyest bit of movement and it will run in sensorless. About 'little load', this is load torque resistance relative to motor torque. With your 300hp a CRX would be 'little load'
For the transition hall-to-sensorless it looks at the hall speed, so with no valid hall signals you can push all you want, it'll not go to sensorless.
The UVW encoder chip has quite a large system on board with analog hall sensor, ADC converters etc etc. A stable supply is essential for its correct operation. Your 15 Ohm in the supply makes a low pass filter with the supply caps, meaning the UVW gets a more isolated and stable clean 5V power supply. I would move the 15Ohm to the 5V line... and my professor (who worked with sensative measurement equipment close to Nuclear Fusion tokamacs) tought me to always ground the isolation on both sides !
See this thesis for the concept: chapter 2 page 13 (19 of the pdf file).... this gets very complex in a hurry