Employee user preferences are considered personal and thus you indeed need to be logged into RangerMSP as the user in order to change their preferences. The easiest way would probably be to use the switch user feature - 'File' > 'Log On as Different User'.
i would argue that settings such as calendar sync should be accessible by the admin user to configure without having to switch between every user, i know first hand how painful this is with 43 employee's