Are you required to provide passport details when booking on shuttle train or ferry to the Netherlands?
While I don't have an complete answer, I think you are quite unlikely to be asked for a passport number when booking this journey. Nationals from the EEA and Switzerland don't even need a passport for travelling to the UK or the Netherlands.
As a test I tried to make a booking for a ferry and an eurostar (train) trip and neither asked me for passport details. See the images below for what the details are you need to provide: