yes, you should look to investors in the area where you are investigating to find their recommendations when building out your team. 

Preliminary analysisI am not sure if it is due to bad definitions in searching criteria.

I have a similar building to the OP where I have an attic with enough space for duplex up or add third unit as part of the ADU ordinance and doing some initial investigation if either option is worth it in terms of the cost/work involvedAssuming the work to run the new water line is another 20 - 40k from a few older comments on BP I remember reading through?

While there are many ways to do real estate, pick one and investigate what is required fir success.

Should I use a private investigator? 

I should have added "preliminary title search" so that I didn't get stuck with liens that weren't mentioned by the seller. 

I would first start a full blown investigation into this lasagna situation.

Mazars, Donald Trump’s accounting firm cut ties to the Trump Organization.The district attorneys office is investigating whether or not Trump’s company improperly inflated or deflated the values of its holdings to secure loans or lower its tax bills.I thought that was the name of the game… and how is that even possible?

I do find it's good to investigate needs and try to address what you can to show the value the day you take over.

Then, after you pay the Prime Contractor all his money you could get bills for thousands of dollars from sub contractors.TO PREVENT THIS LEGAL PROBLEM WITH SUB CONTRACTORS the sub contractors are required by law to give you what is called a Preliminary Notice within 21 days from the time they start work  in most states.