Do you use that separately from Zillow or do you use that as a secondary check once you have found a few potentials on Zillow?    

I'm married but living separate for almost two years. 

Definitely do some more research and/or talk to property managers as I’ve been fortunate that my multifamilies have separate meters.

Are they separately metered for water, or does the landlord currently pay that?

John it's a complex question based on an individuals circumstances.First people need to separate ACTIVE yield versus PASSIVE yield when owning a property directly.

You'll need a separate entrance of course.

-Would the loan have to be 3 individual loans all with separate fees or can it be lumped into 1 loan?

Ther are two separate issuesWho owns the propertyLocating that owner and finding their contact info. 

It may discourage suit from casual potential suit, but the assets are not separated.  

Once the family members with disabilities or who are sixty-two (62) years of age or older, or any other family member, no longer reside(s) in the premises on a permanent basis, or the title is transferred, the property owner shall notify the zoning official in writing, and the accessory family dwelling unit shall no longer be permitted, unless there is a subsequent, valid application.As you can see, it's really all up to the zoning department of that city or town, and my guess is that if your proposed use doesn't meet the above, they will not approve it.It doesn't really sound like they're talking about an entirely separate structure, so if that's true then the question about getting bank financing for such construction would be moot, but it's possible I'm reading the above wrong.As far as whether you can build on the empty small lot in general, you'd want to look up the zone of the lot on the assessor page and then look up the Permitted Uses section of the Cranston zoning ordinance to see what can be built there and Zoning Districts Designated to see if your lot meets the minimum lot size to build something.