All admitted students will be interviewed. Interviews are mandatory for all enrolled students. However, an interview is an indication of interest but not a guarantee of admission.One either will be invited to an interview or simply rejected at the end of July. Best of luck.
HBS 2+2 is a programme that offers admission to HBS for college students that are two years from graduating. You apply in your third year ("2" years before graduating) and after successful admission you work for two years (the second "2") until you go to HBS. So after you get in, you wait four years ("2+2") before you actually go to HBS.