Right now, the deadline for R2 was January 4th, and it takes them about a month to evaluate the apps. The yield for HBS is about 86%-90%. That most likely means that 100-140 from the waitlist (R1 and R2) will be offered a seat at some point. There is no R3 anymore at HBS.
The waitlist is a huge accomplishment, it means that you qualify for their program, but they have too many applications with a similar profile. They want a diverse class, so they want to read the R2 apps to see if they can find diversity there.