I would truley weigh you future life goals and the pros and cons

Not saying you shouldnt worry about it but I dont think 10 year old rent data is particularly helpful in projecting future rents.

I am in contact with someone from their bank and want to check here first before doing anything.On that same note, I'm looking to connect with 2 private money lenders just to network and see how that side of the business goes, and possibly use for a deal that I have going now,and for future deals. 

My initial thought was that housing prices and rents should continue to rise nearby to accommodate the future workforce and current demand, so rental property could be a good investment approach.

I am looking to find a local bank/lender that can provide a commercial loan on my future purchases.

Like I said in the previous paragraph, we are looking at buying more rentals in the future, so you may be asking why we would want to sell this one. 

Use a general warranty deed so it does not cloud title for future sales. 

Move forward with your investment, and use the education you have received on this deal to better your prospects on future deals.

I'd appreciate advice in how to structure this specific kind of deal:- Current owner is a neighbor/friend, who is 75 and wanting to get out of two duplexes in the near future (4-12 months).  

Short-term rentals might fall under Loudoun's new laws about AirBNB-type rentals, which at this time require only registration (taxation and permits likely to come in the future).