So for all three they asked pretty similar questions: (1) what did you do in your undergrad career (research experience etc.) (2) what do you want to do in graduate school (research plan) (3) Why our department (4) what do you want to learn in grad school. (5) what questions do you have for us
Length varies. The one with Yale lasted about 20 mins, mostly because I am interested in syntax/sentence processing, but my interviewers were a semanticist and a phonologist and they were visibly uninterested in my research background and plans (for some reason my POIs that I mentioned in my statement were not there) so we didn't talk much. So I wasn't so surprised that I was eventually waitlisted.
As for Maryland and uChicago, they both lasted around one and a half hours.