I will focus on negating any harassment by the landlord (she is using the ring camera to monitor their coming and going and letting them know she is "watching them.") and helping them find another place in the next couple of months.

HI AJ,It looks like it could be a good moneymaker for you.Nice roofs, nice dark parking lot.I looked at the website for it--If it were mine, I'd change those pics out for modern ones and maybe refresh the site with a new one that showcases the property better.Maybe a 3d walk around camera shot for each unit type (maybe use a local service for this.If it were mine I'd use only low VOC paint on turns, if the maintained shed has high VOC paint, I'd try to sell it to a flipper.$100,000 down on a $2M deal for a (looks like) good roof, sealed and striped parking lot, new painted multi-family seems like a steal.I like this style of apartment with the connected upstairs walkways, they seem to attract long term //forever// renter types.And a pool too...

You should watch their camera inspection as well, is there problem ?

He used smart home technology, sensors, digital door locks, an online thermostat, and outside cameras so he could keep an eye on the comings and goings of his guests.

At the OTHER end, when renting to STR /MTR guests, there may be devices that either provide security, safety, functionality to your furnished rental that you don't want guests accidentally or intentionally disabling or damaging or using,  ie IoT devices, cameras, etc.   

The thing with investing in STRs, it's upfront work (like setting up the ring cameras, dynamic pricing tools, pms) that pays you dividends in the future!

I'm finishing up my first duplex/ rental property and I was looking hire a photographer to take pics I can keep for listing it since they can get wide angles and make the photos much better than a phone camera.

To be cautious, inspect main drains with a camera-snake before you buy and save or negotiate usually about $10k for a replacement or less for sleeving.Electrical would be my second choice.  

I'd get an attorney and think about installing cameras to monitor what is happening to the vacant unit. 

Have him put up a security camera.