One of the benefits to possession is you can rent it out.

Never give them money until they are out, they are handing you the keys, the place is broom swept, and free of all of their possessions.

I would become owner of record after Deed has been filed (4-6 months from what I've seen), but also understand that PA has issues in terms of the length of statute of limitations for adverse possession, and insurability of the Deed. 

Not to mention I am a possessed freak obsessed with the hunt, that's why i do what i do.

The tenant has not met the requirements of withholding rent.If the tenant claims they have moved out, ask them to state that in writing (email or text is sufficient) so you can enter, remove their belongings, and take possession.

Have you gained possession of the house?  

Every time I enter into an agreement to purchase I have the following: Exclusive irrevocable possession and occupancy shall be delivered to Buyer, Buyer’s Assignees, or Buyer’s Agents at 5:00 PM on  the date this agreement is signed by Seller,  on the date of Close of Escrow,  on ________________, 20______ or  no later than ___________ days after Close of Escrow.I have collected my fair share of cash for keys in SS where the lender tries playing God.  

A security deposit is for when they have possession of the unit.

Also, note that an eviction is just a civil lawsuit seeking possession of the property and usually also money.https://www.cumberlandcountypa.gov/FAQ.aspx?

My recommendation for this strategy is to minimize the amount of possessions you have so it’s easier to pick up and move frequently.