The City of Berkeley is getting close to passing a new "demolition" ordinance that prohibits the removal of JADUs ADUs and even illegally constructed units, except under really specific circumstances. 

I only started doing this for my brother because about 9-12 months ago his business started to slow substantially.Then a few months after the slowdown, his primary channel of lead generation, Facebook marketplace, changed their terms of service prohibiting service providers like him from posting services on FB marketplace.He knew I had run over half a million dollars of paid Facebook and Google ads selling various products over the years so came to me for help with Facebook advertising because he could no longer post for free on FB marketplace.

If you only want long term rentals, then HOA should be fine unless they specifically prohibit or limit rentals.

All of the credit bureaus prohibit the use of consumer reports or information for rental transactions. 8.

Have you (or anyone else) seen a municipality where they had a permit process allowing non-owner occupied STRs, then they changed course, prohibited STRs and did not grandfather in existing licences?

The guests thing I can’t find a single source that says a landlord can prohibit guests in their entirety.

BiggerPockets rules explicitly prohibit us from offering our services, not publicly and not privately.

Not prohibited. 

Many municipaliteis across the country have introduced zoning legilsiation that prohibits STR as a legal use. 

I only know of one that goes down to $50k, but fees end up around $5-$6k before title and escrows which can be prohibitive to some.