Nothing more needs to be done.Some MLS systems require the signed withdrawal or you can get fined as an agent.The MLS where he is talking about has zero power over this.He is using a form of the association of which Im the President-Elect.

Two options- pay the Architect to make revisions or hire a Plumbing Engineer to create plumbing drawings.

To locate a property owner, you can typically visit your local county recorder's office or the tax assessor's office.

DMs are a great way to communicate on the site, but you can judge the tenor based on when you received the DM.

I don't agree with your lender that you have to live in the property if you are using a conventional loan, but depends on what product they are giving you, maybe a work around for that.I would not purchase based solely on what income you can derive from STR.

Learn how to budget.

Do you own any investments in Hawaii or thinking of expanding to other states?

If the property is sub-metered/ if you intend to have the tenants pay utilities make sure to mention that to them. 

No matter the market run your numbers and make sure it makes sense for that local area compared to what you can expect.

Is there a limit on how big it can be?