My question is, since we had not receive the taxclaim deed, would we be able to ask a locksmith to pop the lock and enter since those are vacant properties?

no locksmith no hassle of switching out the lock for a different set !

If you keep the model and Key number, you can buy or have the locksmith key to the same Key.

@Ed Mayo,I would take the county's advice and check with your attorney.All you likely need at this point is a locksmith (or a BIG hammer!) 

I give all my residents a maintenance list with phone numbers of different handy types to call and I usually have 2-3 people from each trade they may need (24 hour plumber, electrician, locksmith etc.) on the list.

I didn't expect that, while during the show, I was not sure about the original state of the door lock as people visiting the house might unlock the door from inside, so before I left, I locked it for safety When they arrived home, they immediately sent an email asking me return to unlock that door for them, then less than 20 minutes, they sent another threatening email saying that if I didn't return timely, they would hire a locksmith to break the door lock and I would be responsible for the fee.

You will need a locksmith to set-up the tree and key all of the locks.  

I also left a note saying I would be bringing a locksmith.

Get your Preservation team together, locksmith, website and start looking like you can professionally take care of a banks Asset.

Their move in checklist said that there was a $5.00 charge for any key not returnedI add that any accidental lockout, loss of keys, or requirement for locksmith services is the tenant's responsibility.