I explored the menus and learned how to insert section breaks. As you suggest, I inserted section breaks at the end of each chapter. I was able to make and save a set of copies of the sections as separate documents. This solved all the formatting problems we were experiencing.

Both my editor and I are new to the process of editing a complex document with footnotes in Word. I think with your excellent help we are now working efficiently. I will reassemble the edited and approved sections as they are finished. Finally when all is done I will remove the section breaks so that the final is one long document. All the footnotes will then be numbered sequentially throughout and the file will be ready to give to the book designer...I hope.