Streets and Street Names

How are street names established in San Francisco?

That process is described here.

Why are there no apostrophes or any other punctuation marks in street names that are in the EAS?

Examples include O'SHAUGHNESSY BLVD and SAINT MARY'S AVE.  The street names data that are used by the EAS originate from the San Francisco Department of Public Works (DPW), and can be accessed by anyone from San Francisco's open data portal.  According to DPW staff:

... years ago ... apostrophes and other punctuation marks were removed due to database limitations.

Is it BANNAM PL, or BANNAN PL?  Which one is correct?

The correct spelling of this street name is BANNAN PL, per the official dedication map (between UNION ST and GREEN ST, and STOCKTON ST and GRANT AVE).  Unfortunately, this issue is not uncommon, and is exacerbated by the sign in place, and by the information that is returned by popular search engines, for example here, here, and here.

SF residents fight City Hall to get nameless street on maps (JOHN'S WAY)

This is an interesting article, with photographs, that was published on 04 May 2019 about JOHN'S WAY. Note the use of an apostrophe in light of the information above.