Because the tenant is not responsible for the mechanical features in the building, the landlord retains the right of access with notice.

I think (emphasis on think) I have found a deal for me but here is my situation: I am a recent college grad with no 2 year income (just yet) and I came across this property inHamilton, NJ, in which i need between 100k - 144k after all costs (rehab, closing, 20% down payment) I do not have this money as a 22 year old, so I naturally wanted to get an FHA loan but the problem is, its a quadplex that has all units occupied, so i cant really live here because there would be no space, unless there is a way around this.

Newer roof, good siding, and newer mechanicals.

Going forward, putting an emphasis on tenant retention efforts (easier said then done) is key.

First I suggest you network to obtain better mechanisms to get comps. 

-With new construction there is always a 1-2 year comprehensive warranty along with many longer mechanical & structural warranties. 

But if you are planning in doing several investments, I would say is more advantageous than investing as individual as LLC offers better mechanism to "shield" your investment.

This will help you steer clear of a lot of the mistakes people make when walls are opened up, mechanicals changed, kitchens redesigned, etc. 

If the numbers work I would place less emphasis on the appraised value.

Find an affordable contractor, a repair guy, a property manager, and mechanical contractors.