> ran shadowconfig -on > This gave shadow passwords > > Problem with email > ran apt-get install --reinstall exim4 > read messages I had missed before and put colons into the list of > hostnames. This allowed receipt of mail for this domain.
>From all what you described, these two steps are puzzling. They seem to show that something did not run properly in 2nd stage (after the 1st reboot), which left you with an incompletely configured system. Did the system propose you to create a new user and set the root password after the 1st reboot? Did it ask you questions about configuring the mail system ? (except of course when you reinstalled exim4)

