I don't think it has been established which F/O was in the right seat doing Line Indoctrination training.
This is the dutch text
In de cockpit bevonden zich drie personen, de gezagvoerder, die linksvoor zat. Rechts bevond zich de eerste officier voor wie het een trainingsvlucht was.
I will translate:
In the cockpit there were three persons, the captain, left front. On the right the First Officer for whom it was a trainings flight.
I rest my case.