This looks fairly complete.
I spotted the word "optimze" in there :)
As for the C api, I always cringe when I add an "Ex" function myself, because it feels like I'm spending my last bullet.  What to do if I need yet another parameter later?  ExEx?
For that reason, I have started to use an options structure with a "size" argument at the start more often.  Ugly windows style.
But since these functions haven't changed much for a long time, there is perhaps no need to fret.

I didn't see an "optimize" option to PyZipFile, the original usecase this all sprung out of.