I wanted to open source it at the time...then my employer had layoffs :)
The "React component inside of Angular directive" is fairly trivial and there's a million examples on the net. Just make a directive that calls ReactDOM.render on the element in the link function.
Angular inside of a React component is harder to google for, namely because there's so much misinformation saying its impossible.
It ended up being a variation of the discussion here: https://github.com/ngReact/ngReact/issues/80
(The code in the example isn't quite there...and its been a very long time since I did it, so I don't quite remember the tweaks I had to make).