I have an update on the status of OMEMO in Monal. I’ve completed my spike and have a very rough implementation working. I am able to communicate with Gajim and Chatsecure. I am actually using a lot of the same OMEMO code as Chatsecure using Chris’ cocoapods. The shared code base should reduce duplicated effort and ensure compatibility on the two main Apple platform clients going forward.
The current code isn’t anywhere near production but once I clean it up more, you should start seeing it as an option to turn on in Mac betas in the next month or so. Below you can see my interactions with Gajim and Chatsecure. 
This is amazing work!! Thank you for your efforts!