i like this as a first day of school gift for my kids. Reminder that it's ok to make mistakes. I think I will add a note before wrapping "It's OK to make mistakes, as long as you make the effort to correct them.
I like this as a way of displaying family pictures too! If you still wanted to do the traditional family tree, you could always use this idea for displaying pictures taken in the classroom and pictures with friends - their "classroom family"
Farmer's Market dramatic play center would be an excellent center, which could be tied into a lesson. Depending on the area the school is located, children may not be familiar with farmer's markets, but farmer's markets could be tied into a lesson.