Many thanks for the reply.
Is this macro written by Kino different from <Join files> available under the current NWP (3.0.2) macro? I've tried with this latter, and luckily most of the problems I mentioned have been resolved except one snag: all the footnotes of two of the 7 constituent files appear at the very end of the composite file. The footnote numbers remain, so I know where a given footnote should appear in the main text and the contents of the footnote. The numbering of the footnotes in these two odd files is consecutive.