(1) Any party, or a party's legal representative, may file the written agreement or a memorandum summarizing the written agreement with the court having jurisdiction over the estate or trust. The agreement or a memorandum of its terms may be filed within thirty days of the agreement's execution by all parties only with the written consent of the special representative. The agreement or a memorandum of its terms may be filed after a special representative has commenced a proceeding under RCW 11.96A.240 only after the court has determined that the special representative has adequately represented and protected the parties represented. Failure to complete any action authorized or required under this subsection does not cause the written agreement to be ineffective and the agreement is nonetheless binding and conclusive on all persons interested in the estate or trust.

(2) On filing the agreement or memorandum, the agreement will be deemed approved by the court and is equivalent to a final court order binding on all persons interested in the estate, trust, nonprobate asset, other property passing at death, or custodial property.