I plan to purchase a primary residence, multi-family home (2-5 units, 'house-hack'). 

Reno Scenerio Off Market Purchase Price - $185k ARV = $315-335kReno - $55-65kHolding - $10kClosing both ends - $25k= $335 , $315-$285 =$30-50k gain  As-IS Scenario Purchase - $185kSale Price on MLS :$225- $235kClosing both ends - $20kHolding - $4k= $235 - $209 =$16-$26k gainIn both scenerios I’ll be 1031ing it into a new investment.

What's the purchase price? 

Purchase price: $645,000 Cash invested: $516,000 80% cash purchase.2,437 sq ft Duplex, with 3b 2b for the front unit (1331), 4b 2b for the back unit (1333).   

Gain is your net sales price minus your adjusted cost basis (purchase price plus capital improvements minus depreciation). 

This will be my first home purchase, and I am aiming to invest in multi-family properties.What should I be aware of when purchasing a multi-family property?

I currently own one property, and I’m planning to purchase another.

Self-proclaimed Section 8 guru's online claim to do the latter and then find Property Managers after they purchase the property in whatever state, but I don't know how real that is. 

@Wade Wisner -  Most of the notes that we purchase we keep in our portfolio and borrow against them with private capital.

As we all know, you are really paying for the commission in the purchase price.