First, last and security is normal procedure here in South Florida regardless of the rent price.

It's about processes , procedures and systems.  

real estate related / a financial statement I can provide to a bank when they require one in order to provide me with a loan Every bank will have their set of procedures in calculating your DTI ratio.

This is more along the lines of strategy rather than legal procedure.

You need to know the law like the back of your hand, have policies and procedures in place to deal with problems swiftly/accurately/legally every single time, and be prepared to deal with tenants that push back hard or try to take you to court.

My husband and I have decided we want to try to work through the city's procedure to legalize the in-law unit.

I can't tell you how many labor hours I've lost out on due to their lack of procedures and quality personnel. 

We have an umbrella policy already that I will extend since we have a long term rental in southwestern Colorado.We plan on managing it ourselves and cleaning it between tenants until we can get a developed procedure and checklist worked out, and find dependable help.

I have a lead on a vacant quadplex, but was wondering do I follow the same procedure as wholesaling a SFR?

Many States have similar procedures, rules and regs but they still differ and if you ever need to recover funds on a loan gone bad you will have to follow the law or you will probably be out of luck.