Seeing as the train passes through the structure 3 times I googled "3 stages of a ritual" and this page
Here are the 3 stages as described briefly:Seperation Stage
The purpose of the separation stage is to acknowledge the problems and difficulties that make change necessary and to recognize the need for a person to separate from their former roles or identities that are interfering with peace. During this stage, there is a request to reframe unwanted change into an intention to change.
This stage is often the turning point for acceptance or rejection of the change that is being offered. Participants are asked to leave behind the familiar and anticipate a new beginning without knowing what a new beginning will require. Old identities are let go while new identities are not yet secured. The transition stage of ceremonies usually focus on educating the participants on ways to navigate the desired change.
The final stage of a therapeutic ritual is the integration or incorporation stage. This stage seeks to instill hope for a future that promises growth. Thus, the ceremony is closed with a sense of renewal and confidence that change can be navigated and that peace will prevail. A symbol is often given that participants can take home with them. They are encouraged to let the symbol act as an inspiration to continue with the change.
The description for The Welcoming: Be Chosen tells about a group of people who hate how we're using all the world's resources & that they are not accustomed to technology and we are invited to celebrate their festival of sorts. To be burned alive is quite barbaric so even though it may be called Wicker Man I don't believe the story will follow us being burned alive as seen in the movie. Fire is usually a represenation of being cleansed I guess. However what if it followed the above quotes and we are being initiated and urged to change our ways of life and become a part of their tribe or whatever. Back to being one with nature. The face could be a representation of Mother Nature herself.
As for the human face I hope it does have an opposite facial piece of an animal as Justin has mentioned. However if it doesn't it may look like this: