Hello Adrian,
> So to be clear, all that remains of the database cluster are the files
> you copied out from the data directory, correct?
Yes and no. For the purpose of this discussion, it may be better to say "yes" though.
> That would imply that the server actually started, is that the case?
Yes. The database server's files were not damaged.
> What happened if you connected to another database in the cluster?
That's irrelevant. That said, some were damaged and some not.
Kind regards,
Tomas