Sent this contract to title company with buyers deposit and POF (idk if the title company needs this but I sent it with the buyers permission)5. 

Quote from @Kwok Wong: Hawaii law requires you to give notice; it does not require you to get permission.

I have discussed this with a developer (he is on BP, but I do not want to reference without his permission) who value adds in San Diego by adding units including ADUs.  

Or, if the seller is highly motivated, they might not be able to reveal why they are motivated, unless their client gives them permission to.

I'd think they typically don't approve that, its not a permission issue.

If say real property was held by and used in a trade or business was commercial property titled in and used by the business (disregarded LLC reported on a Form 1040), and you wanted to reinvest in replacement property consisting one or more residential properties (SFR, multi-family, etc) in that disregarded LLC or even in the single member’s name, that would be permissible because they are the same taxpayer.  

The listing agent could act as a dual agent with permission from all parties, or the buyer could be unrepresented.  

This all spurs from a 2019 PA Supreme Court ruling that essentially states that a homeowner has no natural right to run a rental business from their home, they need permission. 

I am a proponent of ask for forgiveness not permission.

You give this person permission in your AirBnB account to access the properties you specify.