Prospective tenants are asked to fill out an $45 application fee which covers the credit/background check.

Rent is below local market getting lots of inquiries but only a couple applications and even those fail to pull the trigger on signing a lease. 

BRRRR strategy (if needed/applicable) to get started on a couple single Family2.

Imputed interest rate rules: https://www.law.cornell.edu/us...Index of applicable federal rates: https://apps.irs.gov/app/pickl...

To be approved they are told at time of application that they must submit proof that each pet has been spayed or neutered and we require that they obtain renter’s insurance which covers their pet(s).

You likly have an emergency contact or referrance listed on the tenant’s application.  

Ive denied three applicants already, with credit scores closer to 650.

Otherwise, to be fair to all applicants, you'd need to adjust for retirement plan contributions, tax deductions, Social Security Insurance, etc.You can always make your requirements more or less strict, just by adjusting the multiplier you require.

I am a new investor with two doors currently, and I wanted to start a discussion on how everyone is collecting application  and application fee's. 

But if you get enough applicants to fill the place with a 700 credit score than by all means you can keep it.