Hey Beth, most of the people I've seen in the space pay by wire transfer or direct deposit.

Should I discuss some bullet points and do a small contract between me and the buyer or is there a standard contract for such that we can agree up on terms prior to handing the deposit to the title company?

We have a holding deposit/agreement in place and the lease is already signed and prorated rent paid. 

What is the norm for deposits in your area? 

But we did not receive the deposit in 24hours.

@Katie Southard For first tenant after we moved who said no way to get to post office during hours, we gave them our keys with signed addendum to the lease that said if they don’t return all of our mailbox keys at lease end, I’m reimbursed for my deposit from their security deposit, and that they are responsible to obtain new keys from post office, themselves, during lease term if lost.

They're fine paying an extra deposit and extra pet fee.

I am looking for advise .We want to move away from security deposits and charge only Move-In Fee.

I do not think it only matters whether you were an employee or an independent contractor- I believe most states would look into how the security deposit funds and rental payments are held/ by whom.  

Let them leave, repair any damages they did (from their deposit) and get it rented to the next tenant after you find out a few things.