I noticed some of the concepts were quite similar to residential apart from a few.

Not concepts.

I recently came across the concept of wholesaling real estate.

But the MI is going to be costly.Four-Unit Limit$1,397,400So you said House Hack and the concept is to buy property live for free!

Everyone needs to read this quote by Ned 1000 times and burn it into your brain til you understand the concept.   

They are doing a similar concept in Barcelona and can definitely advise you.

So, ultimately none of it feels all that risky to me, although for others it is probably a crazy concept. 

"Diminishing marginal returns" is the concept that one can google, both ends of the bell curve suck.

Even if you don't plan doing Section 8, this will open your eyes to how some renters live, what items you should/shouldn't offer when renting "Class C" housing, and also plenty of down to earth, common sense.I'm not a multi family investor (yet) but those books will give you a good foundation with many concepts of buying, flipping, tenant management, and making a profit off long-term holding.

Im not going to keep going back and forth with you because you dont like the concept.