How many units are there in total?

What can we do, I am currently in a contract with this property, it is originally a single-family home and the owner added (3) 1 bed 1bath units at the back (without securing permits).

Do you need to restretch it when the unit is occupied and did she know you were going to do it? 

We are purchasing a 6 unit Apartment building in a small central Texas town. 

I understand that I should have a separate bank account from my personal checking/savings, but based on my research, this first deal won't necessarily provide cashflow with me living in one of the units (it will when I move out).

I've done both a HELOC and a cash out refinance on my current house to buy my 9 units and it may not be the most efficient way to purchase but it has allowed me to own 2.5 million in real estate and have 500k in equity that will grow at 3% or $75k a year with normal inflation.   

If it's just you or just you and a partner, your best bet when looking to house hack a multifamily is to look for uneven unit sizes.

I’m currently doing this with another unit but the owners are selling so I have to move.

I think I'm an accidental owner of a few rental units in the metro-Atlanta area.

Where you are building your wealth is the appreciation and don't forget rents tend to go up over time so as time goes on the unit gets more profitable from a cash flow perspective.