What information, if any, does the previous executor have to provide to the new executor?

The previous executor needs to provide you everything he or she has related to the probate. If the previous executor had an attorney, your attorney should contact that attorney for the file. While I know of no case law regarding successor executors, a successor trustee holds he attorney-client privilege as to every privileged communication between the previous trustee and he previous trustee's attorney. There is an exception when the previous trustee pays the attorney from the trustee's own funds and not from the trust. If the executor refuses, ask the court to have an OSC hearing are sanctions, etc.

You must contact the prior executor and demand an accounting of his estate administration. If he/she does not comply within 60 days you can then petition the court for an accounting. You should be represented by counsel and you should discuss these issues with your attorney. If you are not represented, you should be to avoid delay and unintended negative consequences.

Yes, file a petition to seek an accounting of the executor's actions. Hire your own attorney to get this done.