The guns are entirely different, and share no parts, so I am confused by questions such as the toggle axle on a Mauser C96.
You are incorrect on some of the Luger parts, and I hope you are not in the restoration business. IIRC, Mauser did not use straw coloring. The triggers were blued, the exact color depending on the era. The extractors are blued. The bolt is left white or blued, the safety and hammer are white or blued, again depending on the era. The grip screws are bright blued on early guns, just blued on later ones. There are no other screws in that action.
BTW, the straw color on Luger parts is not a finish, it is the result of the drawing process, the final stage of heat treatment. Trying to duplicate it by heating can ruin the heat treatment (especially on the ejector, which is a spring) and is not recommended. On WWII era Lugers, those parts were still heat treated, but the straw color was simply blued over.
Jim