These lenders are able to do loans for people who are credit-worthy, but don't fit the system that the credit score was made to measure (i.e. the Dave Ramsey community and young people, ha)The BEST resource for you would be to talk to a local real estate ninja who can guide you to the right lenders for this. 

The first thing I would recommend understanding is that your measure standard for downpayments should be 15%.  

This is difficult to believe that at purchase, your cap rate (granted your units valuations are not measured in cap rates but in comparables but the math is the same as others pointed out) is so high unless you are buying D class units in D class areas or getting fantastic deals on C class units.Another observation, you acquired around 50 units in 4 years, a very commendable accomplishment I might add, yet, a desire to get to 500 would take another 30+ years at that rate.

(Our area always requires on-site) water detention)  The solar is very visible and adds some input (Would have to measure ROI)The park-and-leave the car plugged-in is relatively easy to fix.  

Look for contingency plans, risk diversification strategies, and proactive measures to protect investors' interests.

The drivers license is also a small preventative measure against theft, fraud etc...

So that could happen... so I am taking considerable measures to make sure it or anything like it does NOT happen. 

It is just a quick way to measure if someone is a qualified buyer.

Actually, a bank measures your debt:equity before giving you certain loans as well (as they should!).

You can pursue further measures if you really wanted to, I recommend handling it before you do.