Make sure to run your numbers conservatively and based on the current as is value if you plan to go this route. 

I've read BiggerPockets' Real Estate Investing book and am particularly interested in the house hacking strategy, as I'd like to move out of my current living situation.Our main dilemma is choosing between a single-family home (renting out one room to a close friend) or a multifamily property like a duplex or triplex.

To clarify, if my debt on my current SFR rental is 225k i need to acquire 225k in the new property? 

Don't pay the current owner (higher purchase price) for the work he/she didn't do.

The current locations are Frisco, Garland, Richardson, McKinney, and Plano.

Currently the other unit is empty and wasn't sure how to handle the taxes regarding this, so I am looking for refences of an accountant in the Phoenix Metro who does house hack taxes.If you have any other pieces of advice or wisdom for landlord and tenant rights it would be greatly appreciated. 

Take stock of your current credit score and accounts.

I currently invest in OH but am interested in looking into Buffalo too.

As far as rate is concerned, you can usually go about two points over the current rate (less closing costs for a seller financed deal so there is no real expense there) You need to make sure the borrower can cover that.

There are two, one bedroom apartments on the second floor and first floor is currently being used as a convenience store.