sudomod

Does anyone know if this could be a possible replacement for a teensy?

https://thepihut.com/collections/raspbe ... ith-3w-amp

It also comes with an audio output which could be useful for headphones.

I am not sure about the replacement thing, but it is pretty pricey, though.
Even 2 teensy LCs are cheaper.

I believe it should because it has the same microcontroller as the Arduino Leonardo, which does support keyboard inputs (https://www.arduino.cc/en/Reference/MouseKeyboard). However, there might be certain compatibility issues that other members may know about, so don't quote me on this.