The commission shall pay all expenses for the issuance of notices and the conduct of hearings and referenda under this part, and shall supervise the conduct of the hearings and referenda. The commission shall promulgate rules governing the conduct of the hearings and referenda and providing for the registration, prior to the date of the referendum, of all eligible voters, or prescribing an alternate procedure for the determination of those eligible as voters in the referendum. No informalities in the conduct of the referendum, or in any matter relating to the referendum, invalidate the referendum or its result, if notice of the referendum was given substantially as provided in this part and the referendum has been fairly conducted.