It was pretty standardized for all candidates.
I could only remember asking my daughter to point at her facial organs, showed her the 大白菜&大番茄 and asked what they were. Gave her stickers at the end and asked her to push the chair back.
Last year, they only allowed the candidates inside the school premises in batches (a certain time before your interview time). We had to queue up in the 5/F playground according to groups, then listened to the interview briefing. Then we were led downstairs to the classrooms and had a roll call. The candidates would sit outside the classroom and waited to be called by the teacher.
Last year, there was one teacher interviewing one child (accompanied by one parent), but there were 2 or 3 candidates in the classroom (separated by partitions).
The actual interview process lasted 5 minutes.