Ideas for a reunion?

We are planning a reunion for an advanced high school choir (alumni from our one instructor's 20 year tenure are invited) and it's themed "Christmas in July" since we were seasonal. We're composing new music that will be simple to learn, will have a workshop for locals two weeks in advance to help learn the music, a "Christmas dinner" banquet on Friday night for the alumni + 1 guest ea, a long rehearsal Saturday during which we are providing breakfast & lunch, and a concert Saturday afternoon open to the friends/family of the participants followed by a catered finger-food reception. The committee cannot come to an agreement on a Sunday event. They think travelers and local church goers will dwindle our options & we're sponsored (not charging the alumni) so funds are limited. What are options that have been successful in the past- or is being together ALL day Saturday sufficient for this type of event? This is likely the only reunion of this magnitude we're going to throw.