Bernhard Fürst appears to have done a great job putting together an Etherpad Lite plugin. My problem is the Etherpad Lite is an evolutionary cul de sac. Nobody is planning on it becoming a word-processor.
I found CODE which is a free LibreOffice VM offered by Collabora Online.
Great idea but clearly it’s far from ready for production.
What I have found with potential are . . .
WebODF is optimized for creation, collaboration, management of Open Document Format (ODF) and I could be wrong but I believe it’s the only editor that doesn’t need an app installed to work. That makes it the best solution I’ve found for integration in a WordPress/Discourse portal. The man says it uses HTML and CSS to display ODF documents. WebODF is Free Software. Available under the AGPL. Soon it is going to have support for bitmap and vector graphics and spreadsheets.
The Hive.js Editor
A real-time collaboration platform that is modular, scalable, integratable, and extensible. It’s a Node.js-based server with an accompanying web app that works in your browser.
It allows you to integrate your applications with it (so the web app is optional). It is scalable and allows spin up of multiple server instances sharing the same documents for enhanced performance and is integratable through a rich RESTful API and a web socket-based interface. There is support for adding additional interface elements.
Math editor for notational logic.
The only candidate I found for math is GeoGebra dynamic mathematics software.mathematics software, supporting science, technology, engineering and mathematics (STEM) education and innovations in teaching and learning worldwide. GeoGebra is open source software and available free of charge for non-commercial users. You can find our source code online and we are actively collaborating with the open source community and other open source projects used by GeoGebra.