Yes I think learning the disciplines and habits of gaining wealth will take some time.

I'd consider two of the units uninhabitable and the other two are barely habitable. 

Her lease states that after the first 30 days, she was responsible for dealing with pests (although I think that MO law requires the landlord to keep the building "habitable" http://www.ncsl.org/research/environment-and-natur... ). 

Does "fighting fires" constitute using a $20 fire extinguisher to extinguish a small grease fire that would have burned down the unit and possibly other units, potentially harming all tenants?

Start off with just 1 or 2 or more if you have time and pretty soon you’ll be really fast at determining what properties are worth further evaluation and you will build the habit of researching that market on a consistent basis.

Some habit may change, but largely people still go out, and rent still need to be paid.So ....is REIT a good choice to get in at the moment?

In time I would be interested if this causes a shift in residential habits.

We don’t know any PMCs to recommend in the area mentioned, but since selecting the wrong PMC is usually more harmful than selecting a bad tenant, you might want to read our series about “How to Screen a PMC Better than a Tenant”:https://www.biggerpockets.com/member-blogs/3094/91877-how-to-screen-a-pmc-better-than-a-tenant-part-1-services-and-processesEven if someone give you a referral, don’t make the mistake of assuming the PMC will meet your expectations, just because they met the expectations of the referral source.We recommend you get management contracts from several PMCs and compare the services they cover and, more importantly, what they each DO NOT cover.

I've unfortunately had to turnover a few tenants in RI in similar situations, i.e. bad previous landlord mismanaged and developed bad habits or just got bad tenants to begin with.

Somewhere along the way since I heard about BiggerPockets several months ago and begin reading/listening to BP stuff, I picked up the habit of using 30 years when calculating mortgages on properties.