How do I disable DVD player auto start when a DVD is inserted by using Terminal
Couldn't you just copy the preference files? I don't know anything about managing multiple Macs, but there's probably some better way to do this.

Opening DVD Player can be disabled with com.apple.digihub com.apple.digihub.dvd.video.appeared -dict action 1.

com.apple.digihub com.apple.digihub.dvd.video.appeared -dict action 105 will reenable it.

The preference for the desktop picture is in ~/Library/Preferences/com.apple.desktop.plist, but I don't know how to change that directly.

You can find where the preferences are stored by diffing the output of defaults read before and after changing a preference.