Applied to 30, interviews at 6, rejected from 6 so far.
As for late interviews, I did a search for "interview invitations" and looked at the threads from last year. You can get an idea about which programs invite later from that. Granted anything can change, but if a program offered interviews last year in December, I would bet they would do the same this year. Check it out for some piece of mind.
Good luck to everyone.