Hello @frankqc
Scenario A : PoESP32 runs default AT command firmware and is used as unit connected to anther core.
Scenario B : PoESP32 runs alternate firmware, runs standalone and is not a unit.
Re 1. : for scenario B try something like a generic ESP32 board, e.g. ESP32 Dev Module
Re 2. : for scenario A like @robski mentioned the other core sends AT commands to the PoESP32 unit. See examples here - section Example/Arduino.
Re 3. : for scenario B the Groove port should be usable for I2C.
Re 4. : for scenario B see example here.
Thanks
Felix