This one is supposed to work nowadays thanks to:

         if [ ! -n "$NO_ADDONS" ] ; then
           echo "include addons.cfg"    >> "${BUILD_OUTPUT}/boot/isolinux/
grmlmain.cfg"

If there's still a problem with it under certain conditions this needs to be 
fixed, closing this bugreport for now.

This one actually is quite tricky, though I'd like to provide this at least for 
the templates we ship with grml-live by default.

If using grml-live WITHOUT having grml-live-addons installed the bootsplash 
still provides the addons & CO menu. Would be nice if we include the config 
only if the files are available on the ISO then.