You can go as low as 2.5x in some cases but NJ tends to produce enough traffic/applicants where 3x should be minimum unless property is over priced.

What should it cost?

@JD Gunter I agree and should add that I spend 2-10 hours on the phone/zoom with each applicant before I let them into the program. 

But if you want to free up resources for other opportunities or simplify things, selling might make more sense.

2 applicants. 

We use efroms.com for our rental application.

Then you subtract your expenses: (1) Fixed cost: property tax, STR insurance, utilities, landscaping, etc

I thought the regular "free" Stessa account was ok.

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.

If possible, in the future I would try to obtain a copy of a standard Condo questionnaire from the HOA prior to the mortgage application process and ask your lender to review it in advance in order to mitigate some of the time and costs risks associated.