It's natural when starting out to try and uncover every single rock to take a perceived tactical advantage to break through.

You would be able to get better terms on a Refinance for the 4 unit also.Be sure to have a thorough inspection of the properties to uncover any potential problems.Additionally, if this is 2 structures it will increase your CapEx costs. 2 roofs, 2, HVAC's, more of everything.What is the Cap Rate for the area?  

I just cringe though unleashing these techniques of yours on under capitalized folks that will when something goes wrong most likely just walk.. because they will not have the ability basically to unwind these deals in the manner you suggest other than deeding it back.. and unfortunately I have seen way too many not so nice investors really fowl up sellers with this model.. 

A simple free check would've uncovered them for you and saved us all time, (aggravation) and Money."

If so, then you might be a good wholesaler, uncovering off-market deals.In other words, define what you like and don't like, and what you're good at and bad at, and then define your goals a little bit by eliminating strategies that require you do what you're not good at.  

My current situation is as follows: I own the condo I live in, with roughly $50,000 of equity and have a good rate so nice low payments.

With these records I was able to uncover the landlords phone number.  

It's so nice to hear your story of persistence.

I would explain to the seller that once the fact about their property is uncovered, from that point forward, they must disclose it if it still materially exists.

Each property needs 5-10k in improvements... maybe more if I uncover something major. 2 units are vacant. 2 units are filled.