The docs cover some of these but not all. Neither the USAGE nor the UPGRADE files describe what to use in place of use_terse_report in 3.0.
Yes, it's not in there because it's been dead for a long time. It wasn't something that was dropped in 3.0, it was dropped in 2.6.0.
report_safe 0 is the closest to the old "use_terse_report" command.
I never had 2.xx on my system. I installed 3.0 from ports.
Then your ports maintainer made a lousy local.cf file, one that has commands which are from 2.5.x.
Or did you use a tool to build a local.cf for you, and not one that a ports maintainer built into the package? (it would seem very odd for a ports maintainer to include a local.cf. at all, but who knows, some people are in fact on crack)
spamd[1166]: Cannot write to /nonexistent/.spamassassin/user_ prefs: No such file or directory
You seem to be running as root, and as such, spamd is defaulting to "nobody" for security. use -u.