The Rev 1 PCB with the voltage supervisor and pull up resistor changes from rev 2 tested fine using a small perf-board LED setup with USB power. ESPHome configuration was created and installed. The ESP8266 would connect to wifi only on the first attempt. Subsequent reboots of the ESP8266 would try to establish connection with router but would never succeed until router was rebooted. This was annoying and seems to be an issue with the DHCP configuration. Setting the ESPHome board to a static IP address seems to be an adequate work around.
The breakout board was removed and the real lights were installed. They would work for a while sporadically and then turn off. Troubleshooting identified the 500mA poly-fuse was tripping. I tested one of the light bulbs and it used 900mA at 5V. Testing the stock controller showed that the duty cycle was limited to about 15%. The poly fuse was replaced with a pin header to short the pads. Test board was connected to bench power supply and the duty cycle was adjusted to get current draw of about 700mA between both lights. An old 5V 700mA phone charger was cannibalized to finish the assembly for more software development.
Test software posted on github.