I got invitation to uci on 2/16. Not sure if they are still inviting though. My interview is on 3/1. I will ask the people at uci for you if they are still sending out invite.
SLU definitely interviews through April and is still sending out invites. I just got an email from Nancy McPeters (who must work in Admissions) to confrim this.
USC interviews through April. Not sure if they're still sending out invites but I sent them a letter of interest in hopes that it might pursuade them to give me one 🙂