Based on Wikipedia's article about the book, they are probably Rock, Mosskit, Adderkit, and Blossomkit.
firestar,onestar,sandstorm and tallstar are my gess
I think it's Firestar, Tallstar, Tigerstar and Leopardstar. It can't be Rock because he's, um, furless, and Blossomkit is white. The other two are most likely to be Firestar and Tallstar. -AppleDapple11