Make sure to be aware of the different laws and regulations regarding section 8.

I am thinking that is the spirit of the regulation - They don't want you using your 401k to put cash in your pocket. 

The way around it is to use a PPM and set something up under Regulation D of the IRS code, but it's super expensive and you need a quailified attorney to set it up.

Become familiar with what the 6 ADU/JADU regulations allow and their limitations. 

The reason this is important is that it implies that duplexes purchased will be under rent control regulations (assuming a unit is occupied) regardless of if the new owner decides to move in (house hack) after purchasing the property. 

Recently there have been municipalities that have set guidelines (regulations) that prohibit denying a tenant for previous criminal convictions at least x-years ago. 

Regulations.

Obtaining knowledge of foreclosure laws will be helpful as they regulate the rights of both borrowers and lenders in the event a borrower fails to uphold his or her end of a mortgage agreement.

if you have a large group of investors then you should make sure that you are in compliance with SEC regulations.

File a complaint with whatever agency in your state regulates mortgage originators (presuming this person is licensed or registered, which you can check on the NMLS Consumer site).