I can’t find unbranded builds for release & beta version of Firefox for Android.
Many users reported me that my add-on is broken on beta (android). Release for Fx 50 is planned to Nov 15. I really need to fix the bug until the release.
It should work with Fennec. Once you’ve adjusted the IP and port on the phone, you should be able to push the extension directly into your mobile browser from your PC with the --post command of jpm or web-ext.
It would be nice if you could report if this works.