Kids should bring more than three shirts as is suggested. Kids go through clothes with soft ice creams and the like quickly. Often what they say they’ll wear, they actually won’t wear further limiting your choices for clothing. Bring a lanyard for your room keys, kids get lanyards free at the kids club, they will punch your room key at the front desk.
My most prized clothing has been an ultra-thin cashmere cardigan which I could wear over my dresses at night when chilly as well as a satin shawl for formal nights. The cruise ship is air conditioned but not too much only in certain rooms was I chilly.
Finding sweatshirts for adults is easy but not for kids. Make sure your children bring a sweater or zip-up sweatshirt and be sure to bring a rash shirt