The seller had the oil tank removed on March 13th and it had minor contamination.

The property could have liens, some sort of environmental contamination, be designated as a nature area that was set aside for a different project etc. 

If the animal is disturbing neighbours, the tenant might prevent the animal from being outside and limit its exposure to neighbours, if the animal is upsetting a fellow tenant's allergies due to fur contaminating the communal laundry machine, the pet owner can do their laundry elsewhere.

The building has some contamination which isn’t unusual for the area. 

I had gotten information from the seller who has owned it for nearly 40 years that the initial survey was false, there were no issues/contaminants.

means that there is residual contamination remaining at the site and that there are certain use restrictions that must be complied with to ensure the limited cleanup remains protective.

Which result in being exposed to high touch areas and air.On the other hand, people want to feel safe surrounded only by the group, family, or friends they are traveling with, this is great for vacation rentals which are single occupancy, where social distancing is easier and cross-contamination of germs less likely.

A house that old likely has at least some asbestos, and things like soil contamination, abandoned septic tanks, unsuitable soil, etc. could all drive costs WAY up.Do you have financing and or an exit strategy for all possible contingencies?

Asbestos, soil contamination, lead paint, other epaFloor load, what uses can it handle.  

Wells may become contaminated.