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.

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.

My only non-lawyer additions from what I have read and doing DD on a park with LOs:No one really knows. 

I'd rather pay a PM and get an additional $560/Month net. 

Unfortunately, Jefferson county doesn't report beds/baths/sqFT so you can't use that to narrow down.In addition to the Absentee, good deals can also be found by contacting Seniors with Long Time Ownership.

There is an unpermitted addition (600 sq ft) that I can try to permit for about $115 a square foot over my original appraisal, or about $70k.