Thanks @Chris Seveney this brought some clarity to the documents I’ve been receiving lately. 

You would have ongoing filing requirements with the State and would need to keep business records and documentation.

Not why it is needed, but simply paperwork to document that it is a service animal.

Then to activate that you end up Docu Signing 3 different forms mostly containing the same information as if you are a new customer each document. 

Thanks It is not illegal for you to draft a document for your personal use.

What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

Typically we get a copy of their license / identification and pull credit etc after they sign a credit authorization form.Typically notarized documents are needed when recording them with a county, but for a contract it’s very rare to have contracts like a lease notarized.

I just received a package of documents from a lawyer I hired.

I've put together this excel document after reading Brandon Turners "The Book on Rental Property Investing".

Hot tubs and pools have the most well documented ROI.