Do I have the right to enlist the help of a locksmith and enter the condo if they are not home or do not answer (the management office lost my copy of the key, long story)?

Keep in mind, the weakest part of most doors isn't the lock, it's the 1/2in piece of wood holding the deadbolt in place.I saw these at a trade show and mentioned to the guy that they couldn't be rekeyed without the original key, and he showed me a tool that would unlock and rekey them without the original key.

Do we need to change the locks / re-key the unit before giving the keys to the new tenant?

The locksmith idea sounds like a bad one to me.

Yes, get a locksmith to unlock the doors so you can walk thru and inspect the as-is condition.

If you didn't, then it would have been necessary to follow abandonment procedures before you could reclaim your property and rekey the unit.2.  

So today they are having a locksmith open the unit.

I’ve talked with our local locksmith in town and they only take calls during normal work hours.

What do you do to keep your rekey/locksmith charges down?

If you ever go to enter your property, emergency or not, and the tenant has changed the lock, you are within your legal right to have a locksmith come and change the lock on YOUR property.