I think it'll be fine if you just study it more. Making such analogies is not untenable; I have gotten a lot of mileage out of explaining things using the Chinese Civil War, for instance.

A slightly closer analogy would be just using the other entity that I mentioned, the Reichswehr, in place of the Freikorps. Still not great, but it's at least an imperialist organization that the Nazis really did destroy in order to replace it with a much more effective and reactionary force (the Wehrmacht), which did also have members from the old force join the new one.