Welcome Aboard, Rebecca!
Packing for a cruise is a challenge for sure. It looks like you will be on the Disney Magic for seven nights, which means there will be an optional formal night, semi-formal night, and pirate night.
If you choose to dress up in the evenings for dinner, I recommend having a sweater or wrap since the dining rooms are sometimes chilly.
For during the day, your family should be comfortable in shorts and short sleeved tops. I usually pack a light jacket or sweater, too, since I am almost always cold. We have gone on three cruises in January, and have had great weather in all of our ports. (I'm usually coldest in the restaurants or clubs on the ship!)
It is recommended that gentlemen wear pants in the dining rooms for dinner, and there is a very specific dress code if you choose to go to
Palo, the adults-only restaurant. My husband and I love to go to Palo for brunch on a sea day. The food is amazing, and we also don't miss any of our nights in the main dining rooms.
I hope this helps with your packing! If you have more questions, please ask away!
Happy MAGICal Cruising, Tracy V.