When a vacancy occurs, in the office of the Mayor by reason of the death, resignation or disability of the Mayor, the City Council shall elect a Mayor to fill the vacancy, who shall serve until the next general municipal election. In case of a vacancy in the City Council, the remaining members of such City Council shall by election fill the vacancy. In case a vacancy shall occur in any other elective office, such vacancy shall be filled by appointment made by the Mayor and confirmed by the Council in the same manner as other appointments are made, except as to those elective officers which are herein otherwise provided for.