For the next version of Swift Linux, I'd like to cut back on the themes. I know that the IceWM themes are in /usr/share/icewm. Should I just delete the unwanted themes from this directory, or are there specific packages I should remove?

Also, how do I make sure that Menu -> Settings -> Themes will not show the theme options that no longer exist? The menu file in the /home/(username)/.icewm directory excludes this particular part of the menu.

You should be able to delete them from /usr/share/icewm/themes without problems. After deletion, they should not show in menu>settings>themes. The themes that are listed in that entry come from /usr/share/icewm/themes and /home/user/.icewm/themes. So if the themes aren't installed, you won't see an entry.

john