You could have a problem if a fire occurs during rehab with no permit.  

If the property needs foundation, roof structure, fire or flood repair I'd hard PASS on this deal. 

How do you tell your tenants your the new owner and they should pay you rent or you perhaps increase it and you want them to perhaps pay by cash, cheque or an online portal, How would you fire the existing property manager if they were doing a bad job and you wanted to get a new one or negotiate fees etc?)

All of a sudden after sitting there empty for 20 years it's on a fire sale. 

@Chase Keller This will be for my rental so fire dwelling policy

I like to add decks, fences, paved driveways, and fire pit if allowed/appropriate.

As an out of investor wanted to get some perspective from your wisdom: I've got occupied SFH, and my Tenant is not paying:I got 250$/1090$ for Mayand 600$/1090$ for June.My Tenant got fired on April 27th (corona...).She said she entitled for unemployment fee (*pic attached), but she is waiting to get it.

., if the building is multiple stories (elevator), construction technique (fire suppression) etc.  

And I'd fire that lawyer, today, this is simple law so I am clueless why they didn't advise of the risks. 

Also I am a fire fighter as well and I’ve heard I can get some pretty good discounts when it comes to purchasing a home.  I’m interested within the next year in buying my very first duplex.