The realtor's communication with this tenant does not seem to be helping. 2) If she actually moved in, it is 95% likely she may have additional tenant protections due to her age and medical condition.

Also in addition to vetting a deal sponsor, take an alternative route and ask that are currently equity partners in someone else's deals as to what their experiences have been so far.

The additional numbers and info you provided look good if it all goes to plan.

It's 2 bed/1 bath each, and it's on a 10,000+ square foot lot with parking for 4 cars (two garage, two additional off-street). 

There's a lot of value add here, in addition to what's already there.  

Aggressively paying down the mortgage by supplementing the 500$ in cash flow with an additional $1,000 in personal income we would pay the mortgage of in approx. 10 years and save more than 120K in interest payments.

One of my favorite quotes by Jim Rohn is, "Your level of success will seldom exceed your level of personal development".If I was coaching my younger self, this is what I would recommend: Read Brandon Turner's book on Rental Property Investing https://www.amazon.com/Book-Rental-Property-Investing-Passive-ebook/dp/B018UTI2DOListening to the BP Real Estate podcast https://www.biggerpockets.com/podcastListening to the BP money podcast https://www.biggerpockets.com/moneyshowAttend your local REIA meetings to networkStart analyzing deals to get practiceEngage more on the BP forumsAll the best!

In regards to the Borrowers’ front-end ratio, does that figure not take into account the rent cash flow that would be coming from the additional units? 

I know a lien or unexpected issue could hinder selling the property quickly or add additional costs.

In addition to understanding ARVs I have implemented some fantastic software for my company that has all the built in metrics that allows me to create ARV reports in a snap.