Arbeiterverteidigungsbund is not wrong per se, but a lot of nouns packed together in one word. You'd probably separate Arbeiter from the rest of the word.
No worries! Appreciate being able to help.
Personally, of the two, I prefer Deutscher Verteidigungsbund für freie Arbeiter. But I'd drop the 'für'. In that case, Deutscher Verteidigungsbund freier Arbeiter Either Verteidigungsbund or Schutzbund is okay, but upon reflection the latter might roll a bit easier off the tongue. It's certainly less long.
Here's a list of a bunch of German right-wing groups from German Wikipedia. May be helpful:
https://de.wikipedia.org/wiki/Kategorie:Völkische_Organisation
I like Schutzbund (there was a Deutschvölkischer Schutz- und Trutzbund) or Kampfbund (the latter means Combat League, also used by a bunch of fascist groups). Also less of a mouthful than Verteidigungsbund.
Regarding the alt SS, I'd suggest replacing Feldoperationen because it sounds awkward as a name for a group, as opposed to a description of, well, a task. Sturmwache and Leibgarde are both good.
Staatsverteidigung isn't really a term that's used in German, and sounds odd. Assuming this ministry only runs the security forces, the SS expy etc. and not the armed forces as a whole, I'd suggest Ministerium für Staatsschutz (state protection) und Sicherheit. Alternately just shorten it to Ministerium für Staatsschutz (or Sicherheit, but that's quite close to just calling it the Stasi).
If it also runs the regular military, replace Staatsverteidigung with Landesverteidigung (national defence), a term used in Germany and Austria (Austria's modern-day defence ministry is called the Bundesministerium für Landesverteidigung). Staatsschutz is a term that does get used in German to describe combating politically motivated crimes and the like. Of course, here the context is a lot more sinister, to use incredible understatement.