If the latter, how would you approach an increase like that to someone you know on more than just a professional level?

It goes without saying that the flips need to work but i strongly agree with this approach, especially in today's market.  

I'm sure I could find creative financing, but seems pretty challenging as a first investment when average property price is $300k+ for single family.

Liquidity management will be your (and everyone's) biggest challenge.

Never heard of a tenant actually getting a judgment for anything approaching $2M....usually judgments are for mishandling deposits. 

Getting deals to the closing table can be a challenge.

We take a similar approach with some of our buildings and model our numbers with land-value at disposition.

@Ho Eun Park this is a challenging question indeed.

In the 30s, public opinion turned against anything over two units, so finding newer multis is a really binary search - either 1914 or 2014 (since the past decade as Boston approaches peak population again has turned favor back to housing density, and rents warrant the cost to build).

Does anyone have any wisdom on how to efficiently leverage this info when approaching a seller via letter or door knock?