I have a 4k earnest deposit, then the costs of the inspections and appraisals, as well as about $800 remaining for the downpayment, so I don't have too much into the deal cash wise, but I would rather not lose my deposit.

If you don't mind the cat, but need another pet deposit, then ask for that. 

The contestants are a constant reminder of the endless ways there are to generate money outside of real estate, assuming you have the passion to take action.

IF someone doesn't even have the money for an earnest money deposit then they are not likely to be able to pull off the deal.

Beginning with rent for the month of September, please pay your rent by depositing the entire amount into the following bank account at (your bank): account #123456; routing # 123456.

Then I require a double deposit, plus an additional fee to cover a mandatory, professional cleaning after departure.

If they opt not to accept the property by declining to timely give you a non-refundable reservation fee or actually sign the lease with a full security deposit and first month's rent THEN AND ONLY THEN should you process the next applicant.You should not process multiple people and select one subjectively; you're asking for trouble with fair housing when someone claims they were discriminated against.Offer the property to the first one that applies that meets your written standards for qualification.

As mentioned read your lease carefully.My lease states tenant is responsible for duration of lease or until It is rerented and they lose their deposit.

I just read chapter 16 (getting ready to close) in "The Book on Rental Property Investing" and it talks about keeping a checking account for rent and a savings for security deposits. 

We think the Buyer got cold feet and was afraid we were going to keep their deposit, so they ginned up a complaint.