(1) Unless another date is provided in this article or the proposition for assumption of a service by a service authority or agreed to by the board and any local governmental unit from which the service is to be transferred, those services being assumed and those rights, properties, and other assets and liabilities of said local governmental unit incident to the service transferred and assumed shall be transferred to and assumed by the service authority on the second January 1 after authorization of the transfer of said service.

(2) Where a local governmental unit providing part or all of the service being transferred to and assumed by the service authority is located partly within and partly without the service authority, the board, after notice by publication and hearing, shall determine which of the rights, properties, and other assets and liabilities shall be transferred to and assumed by the service authority. The board's determination shall be based on a fair and equitable allocation of rights, properties, and other assets and liabilities. Adequate provision shall be made for payment of outstanding indebtedness as it becomes due, and no such transfer and assumption shall deprive residents of a local governmental unit of any existing services necessary for their health, welfare, and safety.

(3) The plan of distribution provided for in subsection (2) of this section shall be final and conclusive against all persons unless an action is brought by the local governmental unit from which such rights, properties, and other assets and liabilities are to be transferred in the district court having jurisdiction over formation of the service authority within thirty days after adoption of said plan. All proceedings pursuant to this subsection (3) shall be advanced as a matter of immediate public interest and concern and heard at the earliest practical moment. No such plan shall be directly or collaterally questioned in any suit, action, or proceeding, except as expressly authorized in this subsection (3).

(4) Where a service is to be provided by the service authority by contract with one or more other local governmental units, any transfer to and assumption by the service authority of any rights, properties, and other assets and liabilities shall be to the extent and as provided by contract between the board and the other local governmental unit or units.