I think you did well in choosing the wig's style. I do not always think Disney girls' hair translates well to real life, and Ariel's is crazier than most. Understating the big wave of fringe seems wise to me. You are very recognizable as Ariel. The hair is classy and feminine, but the long waves are wild and evocative of the aquatic being she originally was. I think you put your personal spin on this costume while staying true to Disney's design, which is an impressive feat. I would like to see a wig that is less shiny and plastic-looking, but I understand the constraints involved in getting the perfect wig.
You did the right thing on making the dress a LIGHT shade of pink. Its adorable and doesn't clash with her hair. But on not liking the wig too much. I love the length, and the wavyness, but it also looks too fake and shiny, and the bang needs to resemble more 80's hair. But I really think its a job well done.