I can't speak at all to the space station, but my understanding from discussions over beers with American spacecraft MechEs was that Shenzhou resembles Soyuz (and is derived form Soyuz in real ways), but is noticeably larger. This has a significant amount of effects to essentially every aspect of the design making it pretty damn close to a fully indigenous design. They would've had to truly own every piece of the design and manufacturing to make those changes and end up with the flight safety record they currently hold.