I was wondering if the wireless MIDI bluetooth adapter, the Yamaha MD-BT01 supports Android. I would like to use my Android device to play back MIDI sequences via Bluetooth and send the instructions to a hardware device's MIDI IN port wirelessly.

The MD-BT01 shows up and works on Android devices... giving you a MIDI IN and OUT. If your application supports Bluetooth it can access it.

This is very frustrating to get working with Android. What Android app(s) can communicate with this device?

I believe Webmidi (Chrome) can communicate with the MD-BT01. I have an MD-BT01 and I believe I tested Android before loading up MIDI monitoring WebMIDI pages to see MIDI I/O on paired devices. So Chrome is, I believe, one app.

You may need to add a helper app such as:

https://play.google.com/store/apps/details?id=bluetooth.midi.connect&hl=en_US

Soundmondo + MD-BT01 seems to work in android as reported here:
https://www.yamahasynth.com/ask-a-question/soundmondo-on-android

Here's a thread with someone who developed a bridge app - there's an "APK" you can load on Android. Not sure if it's compatible with more recent versions of Android or not. The dropbox link is still active as of today.

https://www.vguitarforums.com/smf/index.php?topic=22055.0

Hope something in here helps.