on esotericism
You have now moved on to asking many questions. I have never heard of anyone saying the Biblical last supper was a spell and that would be an odd idea, as far as I can see.
I would suggest that the esoteric and the exoteric overlap insofar as the Gnostic ideas and Christianity had a complex relationship in early Christianity. Also, in some ways, the St John's gospel can be seen as falling in to the esoteric tradition, as does The Book of Revelation. To speak of the esoteric or exoteric being more controlling would be too simplistic as we are talking of many movements and the course of history.
I think that the idea of the Trinity is far beyond the scope of this post, as it such a complex debate within Christian theology.
Regarding the question of non material beings that is another enormous issue and we are probably talking about spirits. There is a whole tradition of angels, which can be seen as messengers of God and this is in the Biblical tradition. Some others have claimed to see angels, including William Blake. There have been many people who have written books on angels in the new age tradition, and spirit guides which are a related idea.
One of the difficulties is that some of the ideas you are talking about are such a mixture of religion and mythology. Some ideas are based more on imagination than others, especially with the whole genre of fantasy fiction, stemming from the tradition of Tolkien. However, even on a more historical level, many Christians have believed in the idea of the fall of the angels at the dawn of civilisation and this seems more based on the the ideas of John Milton's 'Paradise Lost' than Biblical. So, the question you raise draw upon thousands of years of thought, including religious thought, literature and mythology. As far as the idea of fairies, I would say that this is largely the realm of fantasy and myth although there is the Celtic idea of faery which refers to a belief in nature spirits, which are described as energetic forms which can sometimes be seen in nature, such as in gardens.