I have the newest "L" box with the Bluetooth Voice Remote and it is awesome in Android. I have not tested that remote with LibreELEC yet, so don't know if it functions correctly. The remote is a combo Bluetooth/IR remote, slightly better than my Xiaomi Mibox remote.
Edit: Made a video yesterday for people that wanted to know how the Bluetooth on the Mecool box worked... But again, have not tried this remote with LibreELEC, guess I should get off my lazy butt and try it.
Did you try this box with LE yet? I have this box too now, but cant get it to work neither with LE or CE. When i try to connect it with Bluetooth (device is called "RemoterATV3", then it first connects and then disconnects. I thought that many people have this remote working with LE and there should be no problems. I tried a remote.conf, but when it doesnt connect over Bluetooth, then it wont help me, i guess.