Absolutely require the seller to provide a clean bill of health for the system.  

I would imagine it's not only a losing proposition financially, but also a health and safety issue for their staff.

You pay title escrow transfer taxes and $996 processing, usually there are impounds required.Property has to meet health and safety codes.

For sewer, if there are no sanitary sewer lines, which is common in the country, you will need to have the county health department come and test the soil for a "perc test" that will tell you if your soil is suitable for leach fields that will slowly decontaminate wastewater from your home.

Another point to consider is we have power outages so a generator is a must or near must depending on your health and level of comfort you expect- summer can get to 105F plus humidity. 

I don't believe there's a list of "probate properties" per se. finding probate properties requires you to dig deeper with your research. you can always call realtors and ask if they have any probate properties. and look in the obituaries. or find death certificates by checking with the state department of public health and town vital records. then go to the probate court website for the specific town and type in the name. you might see if they owned any property. it's a lengthy process but one that could pay off. good luck!

There are alot of ways to go, health professionals will likely not need a 3 bed. 

$15,000 of that goes to health insurance.2.  

We have an issue where marijuana smoke (legal in MA) is making its way to upstairs unit (which I own) and severely impacting the health and well being of my tenant.

Look this up to make sure you comply with state laws but here are a few reasons you can deny an ESA:You can deny a tenant with an emotional support animal housing if:They are unable to provide sufficient documentation, such as the emotional support animal letter, that verifies the ESA is necessary for their health and well-being.