The best thing to do is require that the property be vacant prior to closing.

The prior projects has been my biggest hang up

@Dominique Nugent Some advice i received from an attorney after my first business venture (prior to REI) went bad..very very bad.

@Edward Debbs do you have photos and or video prior to him taking occupancy 4 years ago?

If you refer back to your contracts/agreements with your tenant buyers, do the documents include clauses about -- a time frame for them to give notice of their decision in writing to you whether they exercise the option or not; your ability to transition them to a month-to-month tenant should they fail to exercise the option; your ability to market/list the property and offer it for sale to someone else; your ability to conduct showings, inspections, appraisals, and photograph the property prior to them moving out if they fail to exercise; etc., etc.If so, then your good. 

Not sure how I can give her cash prior to me purchasing the home.

Since everyone in this deal other than you seems to be sketchy, I would make certain your i's are dotted and your t's are crossed and get this positioned the way it needs to be Prior to closing.  

I will say that if you have kids or are looking to do family planning you may want to research PG county school systems prior to making your decision

These tenants are bad news, bite the bullet and learn from this experience in how you conduct due diligence prior to purchasing your next investments property 

Laying out your plan and needs to the agent prior to working together let's both of you know what your expectations are.