At a minimum you'd want to work with a mentor or (preferably) attorney that is experienced in distressed property matters and well-aware of the many legal pitfalls. 

I know that it is legal, but is there a problem with me telling the tenants right off the bat that they need to sign a lease agreement?

@Ian MiddletonAttend the biggest networking event in Houston next Wednesday, Sept 19, and you will meet hundreds of local investors, along with vendors.It's a loaded question, but here is the short answer:For legal liability protection, if you need one, is an LLC.

@Manuel Martinez Yes presuming ground leases are legal in your state. 

You should plan on 20% down, closing costs, legal etc. and probably another 10K in reserve funds.You should probably spend more time studying finances, real estate and your local area to get a more complete education on investing.

The property was legally converted from a SFR to a duplex at some point in time.

@Kyle Inbody If you are seeking a Fannie/Freddie loan, your full time student designation does actually count for work history.

Any time a landlord accepts rent payments in exchange for a person to live somewhere, they have created a legally binding lease.

You need an attorney's legal expertise here. 

I have journey level skills in just about all building trades and I am an architectural designer so when I want to wholesale a house I am willing to join my fortune or luck with any of my cash buyers .