At this stage, all I would want to say would be this:
1.) This is a piece of movie fiction, not theology or preaching; it is not made to be religious literature, but entertainment. It is meant to be a scary movie, not a theological statement. It is not a theological treatise, even though the author seems to be drawing on things Catholic writers have argued for a long time. So I would urge people not to see this as presenting a genuine vision of Christian.
2.) People do sometimes claim to have visions of saints, of Mother Mary, of supernatural persons and events. Events are claimed to be miraculous, when we can't explain them. But the Church is very reluctant to give any of these things its official stamp of approval. It's a horror movie that draws on religious themes, and uses them to scare people who want to be scared. It focuses not on faith, but on people's superstition.
3.) In the case of a movie like this, we need to remind people to look at it critically as a piece of spooky fiction, and not to see it as being religious literature in any sense. It is secular entertainment.
4.) If people don't do that, the danger is that will begin to confuse superstition with faith, and see both as simply works of the imagination. Faith is not belief in fiction, but a conviction about what is most fundamentally real, based on Biblical revelation. So we need to keep telling people, "If you do go to see this movie, remember it is made-up entertainment, not a proclamation of our faith. Don't get taken in!"
I don't think it's a good idea to give too much attention to this trailer or the film itself, basically because it isn't making any obvious statements about our faith. The most important thing to do is remind people that this is not about the content of the Church's faith. And don't lead them to distrust the Church's tradition of devotion to Mother Mary and the saints.
With more recent apparitions of saints and of scenes connected with the Scriptures, my understanding is that the Church when it gives its approval of what is reported (which is rare!), is really giving approval to the message being conveyed, rather than offering an interpretation of exactly what the visionary saw. Was the visionary seeing something physical? Was he or she simply having an internal experience, which convinced them they were seeing objects or people? We don't know for certain. But when the Church approves of the vision, as with Bernadette at Lourdes or the children at Fatima, it is simply saying that the message given through this person and event to the rest of us is a message from God that God is at work here, that God has used this person and event to convey his word to us, however it actually happened.
What happens is that when someone claims to have seen an apparition that comes from a divine source, and this attracts attention among a large number of the faithful, the local bishop appoints well-trained theologians to begin an investigation. Often they come to no decision, or even say that the vision was not genuinely caused by God. But in those rare cases where the local bishop is convinced this is not explainable by any other means, and that the message does seem to agree with revelation and Church teaching, the bishop gives permission for the faithful to carry out devotional practices at the site, and for the visionary to promote the "message" he or she has received. A Christian is not bound to accept it as revelatory of God, however it is not seen as part of divine revelation.
A good, reliable book on Marian apparitions, which gives the history of the main ones in the 19th and 20th centuries and offers well-informed theological assessments of them, is Sandra Zimdars-Swartz, Encountering Mary.
