The original Aha still stands: there is no need to transliterate gobs of Leo's python code into elisp or vimscript.
Alas, the Aha isn't nearly so "momentous" as I first thought. Embedding Leo into another program likely will founder for design reasons, regardless of code tricks.
I have abandoned, for now, the idea of embedding Leo into pyzo. Imo, pyzo isn't a good fit for Leo.
Instead, I have begun work on
using pyzo's features in Leo. The pyzo branch contains a copy of all of pyzo's sources in leo/external/pyzo. The following .bat file runs pyzo properly:
python <path to>\leo\external\pyzo\__main__.py %*
This shows that there are no gotchas involved in "relocating" the pyzo sources. The interesting part will be to import only the needed parts of pyzo from leo/external/pyzo, without loading pyzo's main window.
Edward