Kai Syaoran did not want to create empty husks to play as gods. He wanted them to truly be gods or at least as godly as they could be .To this end, simply transforming the life codes of these people was not enough. He had to do more.
Kai Syaoran had learned a great deal about gods from his time with Whiro and when he dissected the Winged Devil god.
Still, this was not enough to create a god. Besides, he could not even create simple animals like rats.
For him to create God needed him to become way more creative. This was the only way since his power was not enough.
Kai Syaoran was intent on making sure that the gods were as real for the Vohohm as possible. In this way, he would be able to control them for much longer and much more easily.
He understood that the gods were not enough to keep the people loyal to him forever but they were just one of the things he had to put in place to ensure that forever was not a delusion.