I’m sorry for answering late, i somehow wasn’t watching this topic. Must have clicked the watching button by mistake in the past.
We’re beginning a UX review right now actually… i imagine you’ve noticed its not great in here just yet. You would be very welcome to be part of that build 
The ReactJS section is here: React Js and Meteor - Public Happiness and you can access tasks in the ‘Tasks’ tab. You are welcome to pick any task you like. If you’d like a suggestion then this one is probably a good one to start with: Hour picker improved
We have a working Android App. I think we needed to update permissions to allow notifications for the latest android version.
We use the stock Discourse App for iOS, which works but isn’t ideal as users need to point it at our site and click on it each time after opening the app to arrive at our homepage.