At any rate, our project was successful otherwise.
At our gathering (with the stealthy help of two nephews) I gave each of the seven siblings an unsewn signature with instructions to do whatever they wanted on the pages - that would be celebratory and have something about their family. We ended up with photos, notes, drawings, quite a variety. Another signature included a list of all the family members in order of birth (or marriage into the family)
One brother is a woodcarver and he made a wonderful box for the book to go in.
I used a binding method that is entirely undo-able if ever needed, but more importantly, that allows for any thickness of pages and will lie flat for easy viewing. (Learned at a workshop at the St. Louis Calligraphy Guild - I believe it was by Micheal Jacobs). My father is a geographer and made several trips to Guatemala so it was appropriate to use a map for the cover. Here's the title page- a piece of Guatemalan cloth wrapped the book inside the box.