The iOS team is going to produce some localized "Buddybuilds" for the Focus app, hopefully sometime this week. These are test builds, which are basically a 2.1 preview of the app.
This means people with an iOS device will be able to test their localizations thanks to these builds.
At the time, only iOS team can invite participants to Buddybuilds. If you are interested, please send me directly an email (not here please!) and I will coordinate with them so you can get access.
Details on how to install Buddybuild can be found on the project's README here: https://github.com/mozilla-mobile/buddybuild/blob/master/README.md