This sounds like an excellent project. It is very relevant to those children and fits perfectly with their local history curriculum. The time that the teacher allocated for students to give feedback and assess each others work is an excellent idea. It allows the children to learn from one another. The idea of inviting the former principal back to review the work is also very good. It is important to have a motivation for the children and i think that if they new the principal would be coming back it would give them something to work towards. well done.