The board of commissioners shall appoint, for a term of one (1) year, by a majority vote of all the members thereof, the following officers, to wit: A city clerk, a city treasurer, a municipal judge of the municipal court, a city marshal-chief of police, and may appoint the following officers, to wit: A city attorney, a fire chief, and such other officers, assistants, and employees as they deem necessary for the best interests of the city; but no such officer shall be appointed until his or her term and salary shall have been fixed by ordinance. Such persons shall hold their respective offices until their successors shall have been appointed and qualified. In case of appointment to fill a vacancy, such appointee shall only serve for the remainder of the term for which his or her predecessor was appointed. The board of commissioners may retain a licensed professional engineer to act in the capacity of city engineer for specifically defined duties, and provide for reasonable compensation for the services rendered.