It used to be standard practice to empty tanks and fill with sand or gravel but that was not an insurance that there was not a leak and that the ground was not contaminated.

Great job, in practice of my calculations you are getting a 6.6 percent cash on cash return from cash in of 40k.

I know that I/we have no tangible reserves at the moment, but we've been hammering down debt like a game of whack-a-mole.Now that we've practically eliminated all of that, I began researching income property.

This has more to do with bad lending practices than anything else.  

How long were they tenants and how often did you do inspections.It is not practical to rely on tenants reporting issues and falls on the landlord to be aware of and regularly inspecting a property for issues.

practice makes perfect

If you do not want to receive unsolicited emails it may not be a bad idea to remove your email address from your profile as a practical matter.

Do you think getting 75% lender financing (20 year term) and 15% seller financing (say 20 year amortization with 5 year balloon) is a reasonable/practical expectation?

If really like to "house hack" for a few years and switch careers and relocate. will I be able to continue house hacking if refinance through an FHA and reuse my VA loan for another multi in a diff location ?

Disclosure is not necessary...this is usually a pretty long and difficult road to qualify to sit for the broker exam...but guessing you will need to practice for a couple years before you can become a broker (this is state specific, though)Good luck!