Regarding storing the luggage the following link from Barcelona Tourism may help:
We arrived at the cruise terminal 12:30, 10 minutes later the staff on the ship invited us for a free of charge sparkling wine, a piece of sushi and a small tour on deck 7 (restaurants, theater,...). Really great ! 2 pm the cabin was open for us and the luggage was on our cabin. A really great service from NCL ! The best service among the cruise lines NCL, Costa, MSC and AIDA.