Any other provision to the contrary notwithstanding, the council of any county may appoint and employ personnel as it deems necessary and prescribe their powers, duties and compensation. All such personnel shall be exempt from the civil service and the position classification plan. Nothing in this section shall be deemed to affect the civil service or exempt status, salary range, vacation, sick leave, service credit and other rights and privileges of any incumbent as it existed on the day prior to May 9, 1977; provided that subsequent changes may be made pursuant to applicable personnel laws.