I would add a USB Microphone
https://www.amazon.com/Kinobo-Microphone-Desktop-Recognition-Software/dp/B00IR8R7WQ/

And a PIR Sensor
https://www.amazon.com/PIR-motion-sensor-HC-SR501-Arduino/dp/B00L9GKN3I/

If I was to do it again, I would call your local glass shops first. I got the same acrylic mirror from Amazon and no matter how careful I was with the frame, it flexes and create a funhouse mirror effect. I called around and the first glass shop I contacted had glass two-way mirror for roughly the same price.

What are you planning to do with the acrylic cement?

I use Volumio to play Spotify on a RPi and the MMM-Volumio plugin to display Now Playing info from Volumio.

https://volumio.org
https://forum.magicmirror.builders/topic/2515/mmm-volumio