Gunning for millennial renters, who supposedly all want to live in major urban cores, and fueled by cheap money and foreign flight capital, massive building has been going on, almost all in Class A assets, and in a vanishingly small number of submarkets.  

I have thought about creating a mobile home park on land but don't want to mess with environmental issues and massive start up costs.

And/or, will you be happy for THEM to sell it later for a massive profit (instead of you)?

Not massive by any means but as we are trying to increase our wealth, every little bit matters.

A massive cost that basically requires either a full rewire of the building or potentially extensive troubleshooting.  

I'd make a final offer and let them decide every single time.Regarding Option A, I'm not comfortable with massively overpaying up front with the sole intention of hammering them in post-DD negotiations.

The economy is ramping up in that area to support the massive drilling/fracking that is to come with housing being a major player. 

----Invest in multi-family unit(s)-Pool money with other investors to do a massive flip-Lend out money for others' RE initiatives---Thank You.

What would be a "small" mistake at 5 units will feel like a massive mistake when replicated with 50 units. :)

This is causing a flood of demand now due to the massive success of key businesses based here.My advice is to do both.You also said you lean towards passive investing, maybe you need to REI passively instead, that might make your perception of the risks change too.