Questions you have above are legit, I don't want to make short story long I see you already understand some important stuff just would love to tell you to be careful and ask about potential foundation issues and wiring. 

Good luck, a lot of people think numbers on the internet are somehow legit if the website is pretty enough.

I have one personal philosophy "rent money especially when the rent is cheap"I found this meme on some social media platform and hijacked it several months ago but it's very true.Rent MoneyThis may be an oversimplification but it's very true so let me apply this concept to a real live flip.

It'll tell you who the current owners or entity is, how long they've owned the property, their current address and you can skiptrace through their platform as well.CheersPatrick J.IG: @SupremeSouthernREI

This is totally legit and common in a situation like this.

I am an avid BP listener and really need to start leveraging this great community/platform more.My story: I house hacked a duplex 2 years ago in a city outside of Boston (Metrowest). 

You can find him on Youtube and most social media platforms.

., but how do you actually validate a property was purchased and your investment in "legit" post close?

There are a number of these groups on social media platforms.

I’m in the metro detroit area, and it’s been challenging to find multi units on platforms like Zillow, trulia, etc.