Though I haven't been in a school interview before, I think you should provide elaboration when necessary, e.g. 'what makes you a good student', as opposed to 'what do you in your leisure time.' I believe if you provide long responses for every/most questions it may be quite tedious. Personally, having long responses for some questions shows your preparedness, but also tells whoever is interviewing you that you have judgement skills, meaning what things to place emphasis on and you prioritising ability. But, at the end of the day, pick what is best for you. Even though I may not know you, best of luck and you got this!!!!