I think Norwegian just extend the winter season into the summer season at the same frequencies, then add the additional summer flights later. I would not take the 2 pw as the finished article.
Maybe but they have just swapped SNN and BFS schedules for 2018 which may suggest it could be the schedule. EDI is also down from 7 to 5 weekly and it would suggest if Cork happens it would be twice weekly unless they increase the number of aircraft.