Naturally Short Girl would be the best name for the shortest unnamed girl in the movie. Imdb lists the Short Girl as Kristen Bone. And it has the quote "One time she met John Stamos on a plane" attributed to her. However that they got wrong. After viewing the Goosebumps episode Bone was I have discovered you are correct. Danny DeVito girl is short girl.
Giselle Sgro I have never been able to figure out.