did Nazis claim pre-existing enlisted officers (that pre-date the Nazis) as their own?
I mean Erwin Rommel predates the Nazis and was just a professional soldier, but they claimed him as their own, even though he himself always thought them nutjobs, it seems.
Rommel was not a SS member. You can learn more about them here, https://en.wikipedia.org/wiki/Schutzstaffel
Germany carried out the holocaust. Sure, the SS is most associated with it, which should not lead to the false conclusion that holocaust was "an SS thing". It was a German thing. Case in point, the Wehrmacht provided large numbers of personnel for the camps and the whole "clean Wehrmacht" idea started out as a defense in the Nuremberg trials (among other popular ideas such as "I just followed orders").
Saying "Germany carried out the holocaust" might be accidentally read as if it was a unified effort. It may not have been.