What works:
Bluetooth, Motor Control, Gyro, Wifi OTA
Wifi is not needed, and is disabled by default.
Either the LetsRobot Raspberry Pi code https://github.com/letsRobot/letsrobot or the Android code https://github.com/btelman96/letsrobot-android will have a mode that sends via Serial, sending commands to the arduino such as f,b,l,r,stop, or any custom commands. The exact raw string it would send for 'f' for example, is 'f/r/n'.
This converts the text into commands for the motors, using specifically a L298N driver, but can use L293D.
This sample is built different from https://github.com/letsRobot/LetsRobot-Arduino , but works the same when receiving controls