I did my spa day at a local salon the day before we traveled. It was cheaper, I got the full day, and I didn't waste any precious ship time doing something I can do easily at home.
Plus I walked on the ship with my pedicure peeking through my sandals, my nails done, my body sugar-scrubbed and my brows waxed. (The day you have these things done, you look more red and puffy than ideal).
Given that you wife and daughter want a mother daughter day, that might be an option for you. Years ago, my dad gave my mom and sister and I a mother daughter spa day for Christmas. It was one of the best gifts we'd ever gotten.