At such election three commissioners for each of the proposed new districts nominated by petition pursuant to RCW
54.12.010 shall be elected to hold office pursuant to RCW
70.44.040. If at such election a majority of the voters voting on the proposition in each of the proposed new districts shall vote in favor of the plan of division, the county canvassing board shall so declare in its canvass of the returns of such election and upon the filing of the certificate of such canvass: The division of the existing district shall be effective; such original district shall cease to exist; the creation of the two new public hospital districts shall be complete; all assets of the original district shall vest in and become the property of the new districts, respectively, pursuant to the plan of division; all the outstanding obligations of the original district shall be assumed by the new districts, respectively, pursuant to such plan; the commissioners of the original district shall cease to hold office; and the affairs of the new districts shall be governed by the newly elected commissioners of such respective new districts. Unless commenced within thirty days after the date of the filing of the certificate of the canvass of such election, no lawsuit whatever may be maintained challenging in any way the legal existence of the resulting new districts, the validity of the proceedings had for the organization and creation thereof, or the lawfulness of the plan of division. Upon the petition of either or both new districts, the superior court in the county where they are located may take whatever actions are reasonable and necessary to complete or confirm the carrying out of such plan.