When notice of any probate proceedings is required by law or deemed necessary by the court and the manner of giving it is not directed by law, the court shall order notice to be given to all persons interested, in such manner and for such length of time as the court considers reasonable. A copy of the petition, any attachments to it and, when applicable, a copy of the will, accounting and settlement agreement shall be served with the notice, unless excused by court order. Any required notice may be waived in writing by: Any competent person; any fiduciary; a trustee on behalf of the trustee and all beneficiaries of the trust; a conservator on behalf of the conservator and all the conservator’s conservatees; a guardian on behalf of the guardian and all the guardian’s wards; a guardian ad litem on behalf of the guardian ad litem and all those whom the guardian ad litem represents; or an attorney under the servicemembers civil relief act on behalf of an attorney appointed pursuant to that act and all those whom such attorney represents.