I'm using non-drowy draminine and will pick up some Bonine as well. I tried the wristbands last time around -- didn't work. The key is to take whatever you are going to BEFORE getting on the ship (which I didn't do last time). Since I was the only one seasick last time, I'm probably not going to worry much about the kids.
As for pirate night, I believe it's the second night of the cruise. We were at Palo that night last time around, so I don't know what they did differently in the dining rooms. However, everyone got pirate bandanas after dinner. The boys will wear that along with their pirate shirts, eye patches, etc. I've bought a small glittery pirate iron-on at a local craft store, so I'm going to put that on a shirt for me. DH will probably put the bandana on his head and maybe wear an understated pirate shirt if I can find one.
Truthfully, I don't think I saw anyone dressed up more than a pirate hat, eyepatch, hoop earring -- and they probably got that on board. It's just a fun party on the deck with characters acting out a play (mickey saving the day), dancing, fireworks, dessert bar, etc.