As far as management, I'd go talk to the ladies in the golf course restaurant/bar.

So far a few possibilities come to mind, but I'm curious if y'all think I'm missing anything.

That would be the easiest way to overcome this.The seller might find that the cost of the lien is so high that he cannot move forward with his next purchase, but that's his problem. 

As far as the numbers, I'm not sure how the cap rate is so high in 2019.  

There is so much work that the good ones will stay busy.

As far as the property tax implication goes, you're talking about two attached structures, therefore should be one parcel- not having two sperate tax bills it seems. 

If what they are doing is so lucrative why wouldn't they buy them all themselves? 

As far as the original question, definitely leave a message.

As far as I'm aware, appliances being included in a rental are simply just to encourage an applicant to lease the property; appliances are not required per-say.As far as "expectations" are concerned, I would say your list is reasonable as to what I typically suggest having available for a rental as they will sustain wear and tear better long-term that providing laundry or counter appliances.Best of luck to you!!

For the rest, it comes down to your preferences, but if it were me, I would cashout refi the duplex owned outright because debt is so cheap right now.