If i remember correctly leaks say that they are Cure Star, Cure Milky, Cure Sun and Cure Moon. There were also their civilian names but i don't remember them anymore xd.
Also i enjoy the gyaru style of Cure Sun, kinda unusual for this kind of show. You know, these are supposed to be character with japanese girls are identify while watching this kind of show and if i remember correctly there's strong ban against tan and dyed hairs in japanese schools. But still, personaly i like it so eh.