Rice has informed some applicants of their decision, either with an acceptance letter or with an interview request. I think the "results" page is likely a good source to keep tabs on what has been sent out!
I don't think interviews are a requirement for admission, but they might be used for the admissions department if they want more information on an applicant. Personally, I never interviewed with Rice, but just got my acceptance last week. I think it completely depends on the department.