Not to mention it would be dick move.If you're asking whether you need to do something legally to terminate the contract, in my opinion, you should at the least make sure you have a paper trail of some sort with the tenant that makes clear that both parties agree that the lease has been terminated. 

Don't risk trying to communicate in person, paper trail is best.

I'd accept that if it looks like the applicant has landed in a stable financial situation, but has trailing credit scores due to issues now clearly behind him/her.I would also ask about employment and income history. 

When collecting first month and security deposit, accept secured funds only - money order, cashier's check credit, debit that shows a paper trail.

Since they are in their 60s, there should be a trail of history if they have been deviant.     

At least you will start a documentation trail.

Your Agent may not like it but she/he is still a player in this one and will be more so if there is litigation.I know hindsight is 20/20 but you really should have invested in hiring an attorney who could have told you whether or not you had a legal/contractual right to cancel and would have created a paper trail of how and when those rights were communicated to the Seller.You stated: "I thought it was all done until I got a call from the agent today asking if he can give the lawyer my number."

Anyway, when the guy moved out he left a trail of damage in his wake, and it has been very expensive for my coworker to remedy this situation.  

I had a similar experience, fortunately I could provide a trail to get the funds validated, but it did add some complexity.

Review my blog post for a nice rabbit trail on a 3FH converted to a 2FH - and the journey to get back to a 3FH.