The property management contract with existing owner does not state it???? 

Does someone has experience with self-showing tours with smart locks or even when an existing tenant shows property to a potential one?

On the other hand if you are wanting to be 100% or close to it debt free and get the purchase price covered from the profit/equity from the existing place than it might be worth selling and buying another place - may be even out of state - North Carolina or Floria or may be even some other states.

I have had several clients work with sellers to offer cash for keys to the existing tenant to get them to move sooner than planned.

Download the SF Handbook 4000.1 starting at the bottom of page 144.A Borrower may be eligible to obtain another FHA-insured Mortgage without being required to sell an existing Property covered by an FHA-insured Mortgage if the Borrower is:• relocating or has relocated for an employment-related reason; and• establishing or has established a new Principal Residence in an area more than 100 miles from the Borrower’s current Principal Residence.

I'm keen to refinance and build a 3rd smaller rental suite under the existing house as it's on a hill and there's a small workshop space with some rock retaining wall that needs to be replaced with concrete foundation anyway.

If anyone can provide that link (if it still exists) that would be appreciated.Thanks!

You need to make sure the policy you have on the property allows for the business use that exists there.  

Because no photos exists pre move in the fact is you don't have any proof one way or the other. 

I saw one of their follow up episodes in which they revealed they hadn't even checked on existing liens, and found they had purchased a house with a $30K lien on it.