With full disclosure that I am not an expert in Safe Deposit rules, these are my thoughts:
1. Yes. Estate Reps have the authority to hire an attorney to assist them with estate duties. The attorney, in turn can perform actions needed to do the job they were hired for. That could include standing for an estate rep who is out of state. Obtain proper notarized documentation that estate rep has retained the services of the attorney for the purpose of managing the estate affairs.
2. This is a tricky one. If there is anything in the box other than the will, it is now the property of the estate, so the estate agent can claim it. In my opinion, it would not be unreasonable to allow the estate rep (or their agent) to collect the contents of the box. I would suggest a creating written inventory of the contents, and have it signed, notarized, witnessed, whatever you need in order to document who was present when the box was drilled and what was in it. Perhaps there are some abandoned box procedures you could refer to for guidance on what would be acceptable for this case.
3. See above. Terminate the box contract for the deceased party. If you have to drill it, a re-key would be needed anyway, and then the now vacant box can be reassigned to a new holder.