Mail out flyers is the best way.You can drive around the area that you are interested and see if it looks abandoned and find the owner.It's off-market so it means a lot of manual work on finding them. do a simple internet search and you will find many ways.

Also, the structure is with interest only payments for 10 years... is that by design or is that needed to pass the minimum ratio to qualify for the loan? 

Just RUBS it yourself, using a relatively simple RUBS spreadsheet and open & transparent billing to your (new) Tenants.

This approach reveals more about the tenant’s behavior and reliability beyond simple yes or no answers.Check multiple referencesContact at least two previous landlords for a comprehensive view of the tenant’s rental history.

You can usually find some events by doing a simple google search.

Really it's burnout as humans aren't designed to work graveyard shifts (look it up!)

How would I do that - send them a formal invoice or request, or can it be less formal like a simple email? 

The local area has a few attractions and similar STRs have done well based on what I see online)The plan is simple. 

I have an interior design business, perhaps I can point you in the right direction. 

Also, as listed on Redfin it is a "Fee Simple Ownership", even though it's a duplexed condo unit in a 4-unit building.