That time of the year in norway can be a bit chilly, so take warm clothing, not alot just some.
On a cruise (depending how long) You need formal wear, this is a nice dress, and your hubby needs a jacket and tie,
casual means dress pants no tie, and for you something with sleaves.
casual means - you need shoes and a shirt/tshirt on, and that in
Remember if you dont feel like going out on a formal night, get room service to sen your food to the room, and there is no clothing rule for that, also there is a casual dining, usaually close to the pool or on one of the upper decks.
there is shops, (dont depend on them to have what you need, as they normally are expensive and badly stocked), but there purfume and watches and jewelery is really well priced.
There are shows, and pools and computer rooms, card rooms (maybe, never been on that ship), and everything you will need. Take a adaptor, of some kind, you never know what the power is onboard.
Last words of wisdom - dont eat alot, (rich food, will make you sick in the end), the food is great, and they never stop giving it to you.
dont drink alot - drink are where they make money, so ask the price or look before signing it.
Be nice to the crew, they dont work for you - they work for your enjoyment. ( as I worked onboard for 6 years). Most of them are homesick and sick of norway and that bloody ship, and every one (crew) on it.
They will treat you like gold, just let them and enjoy the trip,
After working on ships i still think it is one of the best holiday options out there.