Attached to said report of said director shall be the following:
(1) A certificate signed by the director of ecology certifying to the amount and sufficiency of water rights available for the project.
(2) A certificate signed by a soil expert of the Washington State University, certifying as to the character of the soil and the classification of the lands in the district.
(3) A certificate signed by the director of ecology approving the general feasibility of the system of irrigation.
(4) A certificate signed by the attorney general of the state of Washington approving the legality of the organization and establishment of the district and the legality of the bond issue offered for certification.