Just tried it, the extra extensions work now without having to install the beta/nightly and adding a custom collection.

Today, Mozilla announced more than 450 new extensions (software that adds new features or functionality to the browser) to users on Firefox for Android at Mozilla’s Addons.mozilla.org (AMO) Android page. This milestone marks the launch of a new open extension ecosystem on mobile where developers are now free to create and publish extensions and users can easily access and install them on Firefox for Android.