Also, is it legal for somebody in a vehicle as passanger with a CCL holder to have a rifle magazine loaded but not chambered?
As a general rule, the CHL rights do not convey to your unlicensed friend. In other words, the licensee's long gun may be magazine loaded, and the licensee can put a loaded pistol into the car. The unlicensed person needs to have his unloaded.
There is a practical reason not to chamber load a long gun in a vehicle in addition to the legal issue: in general they are much more likely than a pistol to fire from impact.