Zillow's API is no longer offered (or they make it extremely hard to access these days - have had no luck finding an updated link/page for it), Redfin has broad-stroke CSVs you can download that only give 5-10 fields of info and not often at the metro area, you can't legally create a tool to crawl these websites...I'm looking for 1 (or a handful of sources) to pull together basic metrics at the metro/city level for US real estate.

I really see Columbus Ohio as an extremely safe bet for the next 10-20 years.

A one time close is extremely rare for a spec build for investor as most are intended for sale .

Consider if you had a GC build a bunch of houses for you 10 years ago and paid full price (GC Fee) and gave them upside - this would be extremely costly. 

You should not have to go to extremes for hiring an attorney, but you can always consult your Evictions attorney in writing for input on the steps you plan to take-

Go to Etsy and search for "rental property tracker," and you will find hundreds of nice spreadsheets to track 10-20 rentals, usually for under $10.Software has extremely helpful features like online payments, marketing syndication (click a button, and your property is advertised on multiple sites), electronic document review/signing, maintenance tracking, and owner reports.

Extremes in either direction can harm you.

My main concern is the condition of a house through two extreme winters.  

This leaves the tenants extremely frustrated, especially if it's a refrigerator issue causing their food to spoil, or possibly an issue with an appliance leaking water onto the floor, etc. 

Though pricing is extremely important, in that every extra dollar spent on cabinets, is one less dollar in the pocket of the investor or contractor, what is the breakdown of the three above qualities that investors are looking for?