I'm not going to pretend like I know about the first two companies you mentioned. But I know that Krupp was definitely run by the Nazi party. They were responsible for producing many of the Germans artillery pieces, one of the most vital things to combat of the era. There's no chance that Hitler being the state builder that he was, would have not had government control of the principle producer of the Wermacht's field guns. As for the other two companies you mentioned, they may have been nominally "private". But just about all industries of consequence in Nazi Germany were headed by people affiliated with the party. So what you might consider private in theory likely wasn't private in practice.