Not actual extra money out of my pocket,  but saying things like if they're out within two weeks, they get all of their deposit back (even if there was a couple hundred in cleaning and damages).  

We too had reservations about this process because the tenant could easily just back out and say they are not ready to purchase the house at the end of their lease so our lawyer put in the contract that the tenants would need to front $15,000 when signing the contract as a deposit on the house (which we put in an interest bearing account).

Also, if you are concerned, you can always ask a bit more for the deposit.

Would it perhaps make sense to you to form an LLC and have the funds deposited in the entity's operating/banking account.

Is there anyway that I can justify taking these damages out of their security deposit.

A well set Policy Packet should be part of the Lease.. in language... per Policy Packet.As well as addendum for Crime Free / Drug Free,  Lead Addendum, Pet, Security Deposit Agreement, move in condition check in sheet. to mention a few. 

The exact day of 30 days beyond move out who do you think texted asking about deposit.

Because the banks/lenders will ask for (2-3) months of bank statements and if they see a large deposit they will require it to be "sourced" which will then lead back to the HELOC. 

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.

As my main/current bank is a military bank/credit union and I don't like that I cant see all pending transactions and deposits until a certain time (which is a little annoying, I prefer to see it at anytime of the day).