Ubuntu distributions prior 16.04 uses a mix of upstart and SysV. Upstart doesn’t exactly follow the convention of runlevels and process startup in upstart is mostly event driven. So if you don’t find a process in runlevel doesn’t always mean that the process will not get started at that runlevel.
To list all processes in the traditional runlevel.
# sysv-rc-conf --list | grep 2:on
This will list all process in traditional runlevel.
You can view events of upstart by using the command.
This will list all processes and its events.
root@sugar2:~# initctl show-config ssh ssh start on runlevel  stop on runlevel [!2345]