Hi, this is Melanie Hope Greenberg. I received your questions as a Google Alert. The reason you can no longer find my book is that it went Out of Print. I own copies that you might get autographed via my blogs' PayPal.
1)The little girl is the main character of the book.
2) She tells us the time of year the parade takes place, at the Summer Solstice. She tells us the ritual of the Mermaid Parade through a child's eye.
3) The other characters in the story are the little girl's parents. Also the East River Mermaids, their entourage of musicians, King Neptune and Queen Mermaid.
4) The little girl overcomes her shyness and "comes out of her shell".
5) The main character is about 6 or 7 years old and lives in Coney Island. She is shy.
I am the book's author and illustrator.