California... hmm, I don't really like it. You could try to convince them to use the nn as a full name or do
Calista?
Callie or Cali would be nice. Then
Kallie.
Kali looks strange, and Kally doesn't look like it would be pro. KAL-ee, more like KAY-lee.
Cassia is pro. CASH-ah? Trufthfully, I didn't know that. Probably a lot of people will get it wrong, but I don't think you should change it,
Cassia looks nice, and Kasha isn't appealing imo. You just have to tell people how to pro. it the first time and it shouldn't be a problem.