At that 6 to 10 year age of a house, things start to go wrong. a/c goes out, faucets start leaking, carpet gets worn out.If you are going to rent, dont do a rehab on the property.

As you stated, appraisers are looking at square footage, age of roof, HVAC and water heater, electrical, foundation, windows, doors, year built, location.

I can't imagine living with fleas in this day and age. 

As a past software developer, website developer I found TIN oddly lacking in obvious data fields:  beds, baths, age.  

Now days, being the internet age, there are several websites that sell you there programs for finding, flipping, and selling properties. some provide you will everything you need to do it all right from your livinroom and they even have a list of investors willing to buy your property right from the web as well or possibly after a personal inspection .

Unemployment: ideally, % is decreasing over last 5 yearsPopulation: 5-year population growth is increasingPopulation age: 5-year population age range of your target demographic is increasing Industry: ideally, no one industry is employing more than 25% to 30% of the employed populationTop employers: look up the top companies, determine what industry they are in, and calculate if that is a growing or declining industrySupply and DemandIs the supply of your product (SFRs or multifamily) increasing?

- man and wife on mortgages, ages mid-60s by now; foreign names - taxes are up to date on the subject property; not foreclosure (really odd) - mailing address for taxes is different than subject property - this, 2nd property (address for taxes) is REO (possibly also vacant) - phone number for man is disconnected; no phone for woman foundHow do I proceed?  

I'd pay extra attention to the following major gotchas:- roof age and condition- piping condition- appliances/heatingThese can destroy your cashflow and equity. 

Especially if the kids might be the next @Jay Hinrichs.The kids should mainly be able to occupy themselves at those ages, so they shouldn't be a significant distraction.If he is presenting it as here are my kids and we are buying a home, then I think that has a huge potential to backfire. 

However, Facebook presents an opportunity to laser-focus your targeting right down to their location, age, interests, buying power, home value, etc.