Also seems to have a higher entrance point for a solid B neighborhood.

I mean this outside of obvious things like bad location (war zone)/bad quality tenants due to area (I'm guessing usually due to low rent entrance).  

The basement is finished already and has a separate entrance and high ceilings. 

There are several things you can try (former NWCO here)....If you know where the burrow entrances are (there’s more than one), put used cat litter down the hole. 

We have a house without an exterior basement entrance, not sure why they do that.

One is 2+2 and the back house is 4+ 3 with pool. private entrances and income from tenants around $5100 per month

How do emergency crews, ambulance, police, etc access the entrances to  your apartment buildings?

If that was their main entrance, it could be from snow, water brought in from being outside and it just sat on the floor, maybe that's where they left their boots and jackets and water just sat there. the cause could be water, it could also be the floor was installed wrong, if the flooring was installed tight to the wall with no gaps for expansion and contraction then the buckling could be do to that, seen that many times.

Of course, I am kidding :)Believe it or not, in my neighborhood one of the HOA approved color for front entrance door is red, so you are spot on :)

We had a building where the tenants complained/nagged for a dead bolt on the main entrance and then found it too difficult to close and lock the door, so we installed a dead latch - which seems to have solved the problem.Given the low cost of surveillance cameras these days, you might consider installing one.