Kirsten, I'm so happy to hear that Lily is now home with you. As others have said, it just takes time and patience. Not all cats will get along quickly and some may never get along. I was very lucky in that when I adopted my RB Pepper as a kitten he bonded with Storm in just 1 hour. I thought this was normal but now I realise that I was just very lucky.

Right now all of my cats get along very well except for Storm and Cirrus. I've had Cirrus for almost 5 months now and Storm still chases him into my bathroom or under my bed. They may never like each other but only tolerate each other. Time will tell. I'm sure you'll have better luck with Luna and Lily because they're both young. Good luck and please keep us updated.

Please post some pictures when you can.