The cop said that there was enough there to be charged with intent to distribute, but he's only being charged with possession.

I have no lease from the seller, no idea what condition the interior of the property is in, and no idea really about what type of control I will have over this tenant once I take possession (Can I raise her rent, can I have her removed, etc.). 

If they are not served personally or show up in court, you will only get possession of the property and not any sort of money judgement.  

In some states they would still be considered to be in possession until a judge signs the eviction order.

The only document in possession is from his sister that has power of attorney over his late father.What would I need to do to get this deal under contract?

The tax certificate for the first 3-4 years has been purchased by an investor, and after talking to the county it seems like this year it will likely be possessed and put to auction.I've managed to reach the owner through snail mail, who is an elderly couple who called me back and left a VM basically sounding like they don't want anything to do with the lot. 

We've had numerous inspections and site visits with contractors and she is quite aware that when we take possession, that the remodeling will begin in the in law and a large out building but not in the unit she's in until she moves.  

Since I provide the up front cash purchase, I would reap the profit benefits of a flip or take possession of any rentals, which I would likely refinance using the BRRRR method outlined here in BP.My initial goal is to flip 3-4 properties and as I gain knowledge of the area, begin to build a rental portfolio.

What is a Demand for Possession?

An eviction is a suit for possession of the property.