Jan 31st! I hope we hear back soon. From what I understand official decisions come out the first week of March but it seems like it's common for the department to send out unofficial acceptance letters a week prior to that. Do you happen to know if they interview most applicants?
I did't apply to any other programs you mentioned - I applied to other schools, but broadly for international affairs. The interview was quite laid-back, she just asked a few questions from my application. I'm actually not sure whether they interview all applicants or whether this is some sort of a second round of selections.
Hope you hear back from your schools soon and best of luck with them!