Moving Library Collections: Providing Closure
What you do as a thank you for the staff who planned or participated in this effort depends on your budget, corporate culture, and level of participation. Just do something: letters of thanks from Library Adminsitration. My personal bias is not to single out individuals for honors: give awards, etc., to teams. This thing got done because a team planned it, implemented it, saw it through. Acknowledge that.
Maybe have a party for everybody involved. Did your Friends of the Library help? Include them. Do you need to do anything to show appreciation to your patrons for their patience? Did any commercial vendors do anything nice that you should acknowledge in a letter?
Maybe provide t-shirts before the shift begins for all the shifters.
Whatever you do, do something positive and fun to bring a sense of closure.