For rentals, you just need to find out if it's in a decent area, what the cashflow will be, and what the economy around it is like - is it diverse or is it dominated by only one industry?

You're absolutely correct that you can just as easily go to any site and filter through a list of properties in your desired area and price range but I believe their value comes into play more when it comes to details that might not be readily available to everyone. 

The other fourplex was listed at 980 a month so all right in that range. 

How should we adjust for finished basement sqft with respect to coming up with the range of $/sqft that a neighborhood can support?

As far as foundation you will get a HUGE range on prices to fix, from different contractors.

Rates will be in the high 4 to 5%-6% range (depending on buy downs) but this allows you to scale and affords other luxuries (entity vesting option, short seasoning, etc).  

Cranston is well within my range.

I have a colleague in LA who flips SFR's in the $800k-1mill range (with ADU's and they have never came in under valueFHA loan guidlelines do not give detached ADU's value.Though ADUs produce income, lenders cannot use the income to assist with approval as they can rents for a duplex.

You've also done the research already and know the numbers first-hand.Bad: Less diversity in your portfolio.

Most are in the range of $30-50K.