However, the third agent got it listed and sold at a price higher than we were asking over the course of a single weekend. 

Or will it be paid out to each party and when.

Both parties may want to take the cash and run..

If so, that sounds exactly like mortgage fraud (a felony) and conspiracy to commit mortgage fraud.The easy way to test the ethics of a situation is to put yourself in the other party’s position.  

We both know the only way to really do this is to essentially put a second (third?)

Neither party to a contract is entitled to unilaterally cancel it.

After Prop 13 they lost $3 billion – a third of that – overnight.

Execution of a quitclaim deed is relatively simple, and requires little more than both parties signing the deed and, if required in the state where it is executed, having the deed notarized, acknowledged before a notary or with a jurat signed before a notary.

. - This will help attract and keep a quality renterSeek counsel from multiple parties. - You should hear the same advise, or something may be off. 

According to the IRS rules you are considered to be disqualified person to your IRA and as such are prohibited from providing any services to your IRA:https://www.irs.gov/retirement-plans/plan-particip...If you had a long term tenant you probably could get away without using third party property manager, however vacation rental will have high turnover, which will require significant involvement from you, and would be considered as you providing service to your IRA, which is prohibited.