For anyone interested here is an update following my wife's interview yesterday June 15 (she passed!):
Appointment was at 6:30am, their first appointment time slot of the day. Parking booth opens at 6am so don't arrive earlier, the office opened shortly after 6am. As the spouse I was not allowed into the building since my name was not on the interview letter. After going through security my wife said they took biometrics again and directed her to a waiting room.
The interview was in person and the officer explained there would be three parts: civics test, I-751 interview, N-400 interview. Civics test included the questions (who makes federal laws, who is the speaker of the house, what are the political parties, why 13 stripes on the flag, what does the Constitution do, one more) and she was asked to write "Columbus Day is in October." I-751 part included questions about our marriage, where we lived and for how long, and foreign travel. The officer didn't ask to see any documents and said he had everything he needed. N-400 part had questions about the application, what my wife does for work, etc. There was one issue in that she had changed her name after moving to the US and even though she applied for the N-400 under that name and had changed it with the Social Security Administration, her green card was in her previous name and we had not updated that. Fortunately the officer was able to process the change after about a 15 minute wait and she was approved. The whole interview lasted maybe 15 minutes.
The oath ceremony occurred right afterwards and I was able to enter the building for it. They waited until there were about 15 new citizens and the ceremony started about 7:45am and didn't last more than 10 minutes. Afterwards we were quickly ushered out so they could let the next batch into the auditorium, so it seems like they were doing continuous oath ceremonies whenever they had enough people. If you have a very early appointment it's a plus because the office is much quieter before 7:45-8am.
Hope this helps and good luck to everyone. We're glad the long journey is over!