This is awesome! Like you mentioned towards the end, I've been stewing on the idea of a React Native <-> React bridge for a while now too, but haven't had the time to thoroughly dig into the code of other custom renderers to find the right way of doing it. I'm confident that a combination of <a href="https://github.com/web-perf/react-worker-dom" rel="nofollow">https://github.com/web-perf/react-worker-dom</a> and <a href="https://github.com/alinz/react-native-webview-bridge" rel="nofollow">https://github.com/alinz/react-native-webview-bridge</a> would get most of the way there.
Thank you for shedding more light on the not-so-clear world of making a react renderer.