Exporting layer fonts plus merged font?

So I want to create an inline font and provide 3 OTFs in the end:

  1. the regular “solid” font.
  2. just the “highlight” elements, which can be put on top of the solid font
  3. A combination of 1 and 2 resulting in a regular inline font.

I understand from the layers tutorial that I can easily create 1 and 2 as masters and keep everything in sync. Great!
But what is the recommended process to create the merged version?

That would need a small custom plugin.
I made a very simple plugin that should help you: