Thank you for that write-up! I haven't used type hints, fearing pretty much the obstacles you ran into.
The only thing I can (partially) offer is a tool, written by Google I believe, that parses and annotates code with the types the code is /currently/ working with. I say partially because I cannot find it at the moment... ah ha! found it!
https://github.com/google/pytype -- ~Ethan~ -- https://mail.python.org/mailman/listinfo/python-list
