Offer different unit, explain costs of moving out (new security deposit, hiring moving co, cleaning costs, new furniture) 90 days before end of their leaseSend marketing packages or gift packages to preferred employers surrounding property Reach out to old leads older than 90 days

You might lose your deposit, and they would have to put the house back on the market and should disclose that the ductwork is deficient.  

If the tenant breaks it, the tenant's insurance pays for it at the time it happens (not from the security deposit).  

Some repair works needed are as follow which I am not sure if I should deduct from security deposit.

Think of all the things that could go wrong and see if the lease addresses them: unauthorized pets or tenants, early termination, security deposit, lease violations, late rent, eviction, lawn maintenance, parking, etc.5.

Then you can have your Residents deposit directly to that account and the responsibility remains with them.

Due to the low inventory it allows the conversation to be had to get a rent back for free (I have had clients do that just recently, only had a $1,500 security deposit for a $1.2M house), or renting back at the PITI for the new buyers. 

You can require insurance and an extra deposit as well as impose breed restrictions.

The tenant had a $650 security deposit, which I had assumed would come back to me to cover some of the damages.

Keep the deposit and start finding a tenant on your own.