I was given money on the 3rd of August 2018 to hold my rental property for the purposes of (1) obtaining a cosigner (her uncle) and (2) after obtaining the cosigner to build a fence around the property prior to moving in on 25th of August 2018. This fell through because of the uncle wanting to see all completed documents prior to his agreeing to sign the Cosigner Agreement. He lives out of town and was not agreeable to being available for all signatures to be witnessed in front of a notary. He is requesting that I, the Landlord, and his Niece, the tenant, go before a notary, complete the Rental Agreement, the Animal Addendum, all prior to his having to sign the Cosigner Agreement. I felt, if I was to do this prior to his consent to cosign, I would have entered a legal and binding agreement before he consented. This action binds me without his having to sign anything. True or false? Now, what do I do with the monies given to hold the rental?

Unless you have in writing or told this potential renter the money was non refundable then you simply return it in a specified reasonable time (Usually 30 days but local rules apply also, but some refunds are bound by 3 to 5 business days). It depends on what is agreed to, or your past policy and practice. Do you have a policy or procedure for refunds in writing? A verbal agreement or commitment for the refund?

You are correct to not agree to anything until the cosigner had been secured. It can be looked up with a specific county or city. Local laws must fall within the state law.

Statutes & Constitution :View Statutes : Online Sunshine

Or peruse the entire body of statues for something specific to your cause

Statutes & Constitution :View Statutes : Online Sunshine

Without question you have rights, but so do tenants or potential tenants, and without a doubt its in your interest to return someone's money as soon as reasonably possible just to avoid the aggravation and legal haggling. Is there a good reason why you wouldn't?

As noted, it all depends on the terms of the payment. I make all funds for "holding" non refundable, since I am being paid for holding property, I could rent or sell to someone else. But I am clear on this, and it is in writing.

If you did not make it clear to them, you return the money.

And yes, never, never, sign all the paper work, till they have furnished everyhting.