LIN bus ESD protection
I would strongly recommend putting an ESD diode on the LIN line near each connector. The reason is that you don't want the ESD currents to flow into your PCB where they may couple into unprotected internal tracks. This can cause no end of confusing issues that can be extremely hard to track down. If you just shunt the ESD pulse away at the connector, you keep the high voltages and currents away from the rest of your system.

On a low speed bus like LIN the extra capacitance is not going to be an issue, so I can't really see why you wouldn't do this unless cost was an extreme issue. If that is true, you can always put footprints for five TVS diode clamps on the board and then verify on the final hardware exactly what is required.