I am making as assumption that you would evaluate the deal based on expected rents providing that you are including the renovations in the analysis.

Should cashflow about $800 ish a month with both sides rented and 30% assumptions for vacancies, annual repairs, property management, etc.I'm just guessing since a lot of your costs are missing.

Offer to buy the property with owner finance with some money down.For example, let just work with these assumptions and you can adjust accordingly.ARV: $100,000And say she wanted $20,000 to do whatever she wants.

Notice that you can't require a lender to accept any borrower without them agreeing to accept an assumption between you who has requirements to perform and someone of your choosing.

Augustine/Fernandina FL area specifically in either:a) Multi-Family buy/hold purchases that can cash flow with conventional 80/20 financing from day 1 including 50% expense assumption w/ professional property management.

Sorry Jon, but these numbers are not assumptions.  

That email from the seller is very emotionally driven and filled with lots of assumptions as to what profit you will make.

Also, when negotiating with the executor, my assumption is that he won't go any lower than what the mortgage balance is, correct?

Not to mention, that will not solve your issue.I would focus all your money, depending on your finances, on paying for costs of assumption or worst case, refinance.  

With my normal assumptions for expenses and financing I get an 8% cash on cash for a $80K property with $900 in rent.