It kind of took all day and I need a break. But here it is. The companion board has these features:

• USB to UART
  
  • UART or Arduino
• Robot power switch is Off
  • Arduino/UART mode
• Robot power switch is On
  • J-Link mode (C programming)
• Battery charging when USB plugged in
• USB 5V present red led
• UART mode green led, off in J-Link mode
• UART Tx and Rx led's
• Charging blue status led

It uses a FT323RL chip so is Arduino compatible, no dongle needed. Plus UART is nice for C debugging. I tested charging and J-Link, works great. When the new robot boards arrive I'll test UART/Arduino.