God can work and exist within many cultures, but no culture can encompass all of God or His kingdom. The message of Christ cannot be boxed. We are all part of the vast message of the Gospel. But God has very specific and unique ministry for each of us. He gives us specific tools, spiritual gifts, culture, sensitivities, friends, experiences, and our own personal road to the Gospel. Just like each of CS Lewis' books emulates a different angle of the Gospel (which is the same with every book of the Bible), even within the stories each of the children find or meet Aslan a different way. Lucy definitely came to Him differently than Edmund, and even more different for Eustace. And Susan, who had the same experiences and revelation of Aslan's glory, she still decided to seek her own glory and life.