Just to try to be clearer, currently I am not concerned that their water heaters will leak and flood the unit I want to purchase (they are a floor down from the living space), but that because the only access to their water heaters would be in my unit, that I could some how be responsible insurance-wise or legally.The seller of the unit represents his mother (who recently went into a nursing home and cannot make her own decisions).

The question rarely gets asked of clients because the underwriter can just look at the mailing address and the rental address.I would state that your contractor is representing you in a PM capacity. 

Another exact unit in a sister building was listed for $192,900 and an offer was accepted yesterday (in the 80's says the broker I spoke to who is also representing this unit).

I represented myself as the buyer 😎

The Lease will detail everything that you need to be protected, if you don't have a commercial broker, definitely look for an attorney to represent you. 

IF you can find an investor friendly park there are however many owners willing to offer lease to own options which can represent a low cost entry point for you. 

The different markets in this area can be vastly different from one another and I would be doing them a huge disservice to lead them to believe that I can represent them on a home in Sacramento.

It’s important to understand this because this is why the seller’s realtor will try to get you to buy the house through them (if you’re not already working with a realtor - they aren’t allowed to poach) - if they represent both the buyer and seller, they get 6%!

If you do not use an attorney, there is no one in the transaction who is representing you.

Johnny is representative of lots of people actually, but yeah I'll go back to my line about "if you want to borrow from Aunt Fannie Mae, you've got to get right first with Uncle Sam."