There are 8 main LIs are those 3, as well as Alice, Ava, Bobbie, Bonnie and Imogen. Those are the girls who get variants of the ending, although there will also be more prominent side girls who might get as much content, but just don't have there own version of the ending.
Lucy and Chloe are for sure some of the more prominent side LIs, they'll both have a fair amount more content. And don't worry, you're not the first to be disappointed Lucy isn't a main LI, she's certainly got a lot of fans
