In CA currently only MF properties are rent controlled.  

School system?

This is a common issue, but having stricter cost control measures or a contingency buffer in place could help on future projects.

We also manage 2 other companies together that require accounting systems. 

Also it would be interesting to control for attributes such as 1) condo vs. fee simple and 2) modest vs. midrange vs. high priced homes.

From the liability/asset protection side always use licensed and insured vendors, build out a robust contract management system, make sure the owner is always listed as additional insured.

Ultimately YOU need to be the one in control so YOU need to understand what's going on more and you need your agent to assist you with that.

Many people tend to think that the Federal Funds rate controls interest rates. 

Two codes of specialized paint for order control, not the regular Home Depot paint, were necessary.

It’s just  that I have no accounting experience and I created my own spreadsheets when I started this (I created and know my own system, not this one).