Last Christmas, I gave two of my best renters $50.00 gift cards to spend however they wished.

SO the question is how soon should I be creating an entity, LLC, creating a website, printing up business cards, marketing, etc.?

Leave your credit cards and any money in your wallet at home.

As soon as he points the finger that it's actually your house and you just had this arrangement in order to get money from the bank for doing work on your own house, your whole house of cards will come tumbling down.  

I think credit card debt is probably the obvious category that needs to be kept a little to zero balance due to typically high rates, but what about auto loans?

Either he or she or they, probably him, got mad and took it out on the property, if you knew about it sometime ago, you should have terminated the lease, committing a crime or assault or having a lover's spat isn't a free card to destroy the property anywhere.

I came out of the deal with 15k in equity but in the process I ran into a lot of unforseen issues that resulted in me maxing out my credit cards just to obtain the occupancy permit and to start prepping the house for resale.  

It syncs up with all of our credit cards, auto loans, mortgage, and banks.

Yellow letters, professional letters, zip letters, text postcards, pictorial/full color postcards, greeting cards...etc, will all appeal to different people. 

The landlord pays for the reports by credit card and collects the fee from the tenant.