1) If each is running in its own terminal you can CTRL-C to shut each one down. A kill quit should also work. No matter how you shut it down (ctrl-c, kill quit, shutdown) the same shutdown routines are run.
2) No. Shutdown works by accessing the jmx server via jndi, which means that shutdown needs the host name and jndi port number. There is nothing in the shutdown code that will search the configuration information looking for that information.
3) The -n option is necessary only if you change the name of the serverimpl mbean.
4) Both the jmx console and shutdown use the same entry ino the app server - if you secure the jmx console then you will also have to supply the credentials when using shutdown.
Using individual terminals, Ctrl+C/quit is not an option for me. So, it does look like there is only one way to do this, that is use the shutdown command noted above.