Essentially any individual, even other Kryptonians, can be prepared and serve as a Kryptonian vessel. With the possible exception of Brainiac, who Zod never thought to possess, either because he's a machine and can't be possessed or because Zod felt disgust in possessing a machine. Serving as a Kryptonian's vessel gives the individual the powers of the Kryptonian at hand. Besides Brainiac, who's a machine created by Kryptonians, Kryptonians in vessels are still vulnerable to the various types of kryptonite.