I have heard they did away with the item you can drop off at guest services and get signed but I don't know for sure. We did that last year on our first
Disney cruise, we had pillow cases signed, so awesome! We also did the Bippity Boppity Boutique and it was SO WORTH IT! We did the cheaper package and brought our own princess dresses on board, the girls really enjoyed themselves and when they walked into the dining room that night, dressed up as princesses, the dining staff went above and beyond to make them feel like real princesses!!

We also decided last minute, once on board, to do the BBB for the pirate night, it was very reasonable in cost, we had our own pirate shirts already so the girls just got made up into a pirate at the BBB with makeup, a pirate kit, etc and that was by far worth the little we paid! Highly recommend!
Also, take part in pirate night as a family. We just took pirate tshirts, didn't go too all out but enough that we had fun with it.
Take a highlighter and highlight the navigator daily on things you would like to try and do, meet and greets you want to make and that way you have things lined out. Just know that most characters will be on the ship all week long so don't try to do them all in one day. The kids club is phenomenal! We cruise on Carnival the year prior to our Disney cruise and the kids were not fans of the kids club on Carnival so they were very hesitant to try Disney kids club. First day on the ship, they tried the club, Mickey and Minnie made a visit and they were sold for the rest of the week, they loved the club! Do not be afraid to leave you kids there, the staff is amazing and the club itself is awesome!!
Most of all just enjoy your cruise!!