Went to file the paperwork with the court to find that the laws recently changed and my notices didn't give the tenant enough time (non-payment went from 3-day to 14-day).

As soon as I had the deed in hand/ closed on the property (bc I was in the same boat with Auction.com and didn’t want to jeopardize the sale by approaching occupants) I would have my lawyer draft the first notice letter and print me a copy that was being mailed (that should be a nominal fee - the court fees and later on is when the lawyers make their money).

Jason Childs, Opendoor’s chief financial officer, said the company’s geographic diversity and 90-day average flips helped shield it from a potential housing market crash.

I just received a call from an attorney who is apparently representing them and it looks like they are trying to milk the process and go to court so they can reside in the apartment rent free for now.I am anticipating hiring an attorney, but any insight would be appreciated.

You can keep adding cosigners but at the end of the day, it's hard to collect from one without going to court. 

My attorney is still reviewing everything, but has given me the following bullet pointsThe old 3 day non payment demand for rent is now changed to 14 daysA tenant can automatically ask for a 14 day adjournment at court and have it grantedOnce a warrant has been issued, it cannot be enforced for 14 days (changed from 72 hours).A tenant can request a hardship and be granted up to 1 year to remain in the unitLate fees are capped at $50 or 5% of the rent (whichever is higher). 

The court has the resources to help people get involved in that.

In other words, you may have a court case and should consult an attorney.

Verify previous landlord, verify employment, check local criminal court records for their name. 

Google Portsmouth, VA HUD investigation, police chief, city manager, etc. and you will see the drama that is always going on.