If you are and estate executor can you appoint someone of your choosing, relative or legal overseer to take your place?

The answer should be in the Will. Generally, if one person cannot serve, another has been designated to serve in the documents. Rarely, is someone given a power to appoint a replacement. You mentioned that someone has the power of attorney . A power of attorney is ineffective when the principal passes away and the agent (holder of the power of attorney) may not act, as a matter of law. You may want to consult with an attorney who can interpret the documents you referred to.

Attorney McMahon is correct. A successor executor is likely named in the will. The only time, typically, that an executor can name his or her successor is: a) there is no available successor; and b) the will gives the executor the right to name his or her successor in that event. Finally, it appears that the person hasn't died yet. Accordingly, the person (if legally competent) can change his or her will to order the executors in any way that he or she pleases. Good luck to you.

The contents of the Will are controlling. If the will does not give an executor authority to name a replacement, then your State's statutes will control. I doubt very much if the statutes permit this. The Will may give you the power to hire experts such as attorneys, accountants, appraisers, etc.