True about the semi formal and formal and the Pirate night. When we sailed in January, it was still advertised as Pirate/Caribbean. I wore a cute bright colored wrap and my DD 4 (along with most little girls on the ship) wore a bright dress (or two piece outfit) bought at St. Maarten for about $10. Perfect for the festivities.
You will see everything, really formal, cocktail, simple dresses and pants. Remember black pants can be worn numerous nights with different tops.
Enough you time on the magic.