Best thing to do is try to track down the heirs and make them an offer.Just saw a place this week that had 20 years of back taxes and had not yet gone to foreclosure sale.

I am tracking but think the very thing you are referring to is why Airbnb came into existence- to not be like hotels. 

I'm trying to figure out how to set up my 4plex legally to protect our assets and also keep track of each property.   

You will know exactly what is in each house, what the measurements are, etc. this means that if you have many you can have a standard depreciation schedule for them, it also means you can track statistics on repairs (a quote for a single home is completely applicable to any other property), how long appliances last, etc.

This is coming on the November Ballot --> "Justice for Renters Act" Can't say, as a native Californian and investor that I'm too excited about this one..It will all depend on your goals and risk tolerances.

It would be a different story if you were buying something that had a proposed development, train tracks, road, etc. 

Track every single expense and account for that in your return.

Typical requirements for a HML: recent bank statements, credit report, appraisal/BPO with as-is and ARV, sales contract, scope of work/budget-draw schedule, track record/previous purchase and sales HUDs/ALTAs showing the construction holdback amount, etc.

Matthew,Based on recent investor track records I would say choose Ohio over NY or NJ for a 2-4 unit. 

I would say you are on the right track.