--- So if you are not sure and need some more time and help from others who are more experienced than you --- you need to CONTROL the property - you could write a clause in your offer (use a *skinny contract offer) that will give you some time to perform a skilled *Second Stage Negotiation.The clause you want is "Seller hereby grants to Buyer's agent, employees, engineers, contractors and others to enter the Property upon reasonable notice to Seller, at any reasonable time for the purposes of performing tests and other investigations to be performed at the sole expenses of Buyer in accordance with the following conditions: ..... 

Video pipe inspectionFor this I use Tunnel Vision.If anything is found in those three that warrant further investigation, the inspector will let you know.

Like finding out more about the property,investigating public record, checking current market value, etc.

So a list comes out, you investigate the homes by visiting them, a quick title check, etc.  

If forced to “legalize” it with permitting, either ask if they have “prescriptive measures” for deck framing you can review and see if it matches, or hire a Str Eng to investigate and draft a plan that matches the deck + any retrofitting they feel is necessary.

Now, the odds of this women being investigated by the IRS are no doubt slim.

I'd investigate that first.  

He says the 30 meet his criterion but that the 10 "warranted serious investigation."

From experience, the WSJ does not spend enough time investigating their sources and their younger staff is seeking a scoop that will increase their reader following.

You need to investigate why the market has declined.