Much empathy to those dealing with rejections. Last PhD application season I was rejected across the board. Did an MA, applied again, and now have several options. Academia can be a brutal game.
I don't know if they interviewed all finalists, sorry. I do know their "short list" wasn't particularly short, so it's entirely possible they didn't interview everyone.
First post from a long time lurker! I doubt Chicago is done announcing acceptances. I interviewed last week and was told that we will hear end of this week at the earliest, but more likely next week.