I know property managers in every state who use non-refundable application fees and it is the standard for every class of property and applicant.

You looked past a red flag right at the outset:"When application was made tenant was I am not going to to have my puppy with me so do not need pet fee or application"Total red flag.

This criteria happens to pretty much exclude all S8 applicants. 

Here’s an example of what I've used if they don't qualify based on what's on application. 

Quote from @Teekap Pate: Hello, I have my first tenant application for my investment property come in.

I have an applicant who says she lived in the Dominican Republic prior to the 2 years she's been at her current address.

I encourage you to consult with a qualified attorney to ensure this agreement complies with applicable laws in your area.

A) Landlord denies application from tenant with ESA.

The advice is downright bad; not applicable to the average Billy & Barbara, some signs of bragging among other concerns.

For example, I mention that every adult must pay a $30 application fee, pass my credit/criminal background, make a combined income of 3x the rent, and whether or not the property accepts pets.