Quick anonymised dump from https://code4africa.slack.com/messages/general/
I saw statsSA host a open data site of sorts, but there's no info about it that I could find, will keep digging
Also, it ain’t a policy as such, but X is helping drive digitalisation of municipal bylaws by local volunteers through the excellent http://openbylaws.org.za/ initiative. You might want to sign-up for some of the cities you mentioned above?
this is a good start: http://opendatahandbook.org/
ekhurleni has an open data portal