I also had Skype interviews with professors from Brown and UIUC. The PI at Brown got in touch a week after our Skype conversation to let me know that, unfortunately, I didn’t make the cut/ wasn’t invited to official interview weekend. I believe that, at this point, all official invites have already been sent, but I could be wrong.
The PI at UIUC told me they didn’t have interview days (just visiting days for students who were already accepted to the program). He contacted me afterwards to extend the offer.
I also applied to Booth (Behavioral Science) and Harvard, but I haven’t heard anything back.