Yes you should keep working with your chairmans team after you submit it. Like Jessica said it is a good idea to work with the students on making displays and working on the bullet points to say in the interview so the students can learn to keep the presentation under 10 mins. (I always have trouble doing that at demo's
) Also anything that you would like to show the judges like team year books and info on things you did during build that are not covered much in the submission.