I know it's easier said than done because waiting sucks, but I don't think you guys should be too concerned. I'm sure you'll hear back soon.
I didn't get interviewed. I wonder if you guys got interviewed because you qualified for the fellowships. And maybe that's why your acceptance notification is delayed because they have more processing work to do.
or
Where are you guys from? I have nothing to back these possibilities up, but perhaps California residents get notified faster than non residents...?
Good luck! I hope you guys hear some good news soon!