Last year, they asked about 5-6 families going to a classroom together. The kids are sitting next to the parents. They asked every kid to stand up and introduce him/herself one by one. The teacher would ask some simple questions and each family to talk about their opinion. It's ok that our group's parents are all quite humble and we just shared our opinions one by one. I think they just have a quick glance to see if there's any monster parents only as I didn't see the teacher marking anything. No need to be too nervous. Some kids will have offers in 1st round even no 2nd interview.
I will give up as 1.5 hours way too long. Don't want to scare my child. She may think other interviews also that long and will be reluctant to go to other interviews.