> (1)  Upon string creation, do we want to *promise* to discard the UTF-8 and wstr, so that the caller can memory manage?

I don't understand the question. Assuming "discards" means "releases"
here, then there is no API which releases memory during creation of
the string object - let alone that there is any promise to do so. I'm
also not aware of any candidate buffer that you might want to release.

> (2)  PyUnicode_AS_DATA(), Py_UNICODE_strncpy, Py_UNICODE_strncmp seemed to be there in the code I was looking at.

That's very well possible. What's the question?

> (3)  I can't justify the born-deprecated function "PyUnicode_AsUnicodeAndSize".  Perhaps rename it with a leading underscore?  Though I'm not sure it is really needed at all.

Nobody noticed that it is born-deprecated. If it really is, it should be
removed before the release.