Probably. You may check usual places to arrange consult.

Yes. However, court has final authority to accept or reject your agreement.

Impossible to opine based on out of context information provided. I need to see trust, ,any amendments, deed o further advise.

Judge not required to accept mediation agreement. Judge has power to reject or amend.

Possibly. Probably no worth effort of suing.

No. If you reasonably believed intended target was being served you are no liable.

Begin by hiring probate counsel to investigate validity of RDP and respective rights of DP, child, parents and siblings.

You are almost there. Hire probate counsel to complete estate administration and close matter.

Possibly. Depending on POA terms, it may/not be valid and surviving agent has continuing authority to act. I need to see POA to further opine.

Hire counsel to demand release of cremains to you.