We had the legend of the outlaws of Dorthonion be common knowledge in places far from Dorthonion early in Season 6...because their brave deeds make a good story and people wanted to talk about that! Beren is 'a living legend who lives up to the legend' in his own lifetime. Orodreth and family discuss the outlaws of Dorthonion in Minas Tirith in Season 6 Episode 1. And when Lúthien introduces Beren to the court of Doriath, she does so not as a random stranger, but as someone whose history and deeds are known.
The tale of the quest for the silmaril and the wedding of Beren and Lúthien are definitely going to be news! Carcharoth's swath of destruction was not limited to Doriath, so any tale of the wolf naturally would raise interest in what caused his madness and what became of him. The quest took Beren and Lúthien to Nargothrond, and involved the people of that kingdom in it. They have more than a passing curiosity to learn how it all worked out! Any story that involves defeating Morgoth is going to be THE story.
The only fully isolated kingdom in Beleriand is Gondolin. Everyone else trades with the dwarves, welcomes travellers, and has interactions with people outside their borders (some more than others, naturally). Turgon gets his news from the eagles, who were directly involved in the quest for the silmaril. They know how Beren and Lúthien got from Angband to Brethil! They met and spoke with Daeron, who told them Lúthien's story to that point. They spoke with Lúthien while transporting her. They are going to have an interest in finding out what happened to these people whose story they became involved in.
Nargothrond and Doriath are both fairly isolationist during this time, but neither has absolutely closed borders. Túrin is in Nargothrond from FA 490-495 (at Gwindor's invitation). During this time, Finduilas falls in love with Túrin, and turns away from Gwindor. When they discuss Túrin, Gwindor warns her that Túrin is not Beren, and that she should really think twice about marrying a mortal. Gwindor was imprisoned in Angband during the Nirnaeth Arnoediad (FA 472). So, this suggests that news of the story of Lúthien, princess of Doriath, marrying the mortal Beren had spread to Nargothrond prior to the Nirnaeth Arnoediad...which is unsurprising. Again, an army from Doriath showed up on Nargothrond's doorstep demanding information on Lúthien's whereabouts and in response for a marriage proposal written by Celegorm. News of her wedding to Beren is something that the people of Nargothrond are going to care about!
As for the mortals - folk of Brethil tended Beren's maimed hand, attended the wedding, and encountered Carcharoth. They are part of this story. Those same people then moved to Dor-lómin, so news of the story would have travelled there as well.
So, going into Season 7, I would say it is safe to say that it is common knowledge throughout all of Beleriand that:
- Lúthien defeated the sorceror at Tol-in-Gaurhoth
- Beren and Lúthien entered Angband and stole a silmaril from Morgoth
- Beren and Lúthien got married
- Carcharoth was killed in Doriath
- Thingol has a silmaril
The death and subsequent return of Beren and Lúthien is one of the most shocking events in their story. Surely that would be talked about as much as the other things! But I imagine there could be confusion, disbelief, and multiple versions of that tale. I recognize that this is not an era of instantaneous communication, but people do interact with one another, and legends do spread. While it would take time for the tale of Beren and Lúthien to be told in full or put in the form of poems or songs, there is significant interest, and it does not take a ridiculously long time, either. Their deeds were very public - these were not secrets to hide. So, given a few years...most people have heard their story. It does not take a full 50 years for this story to spread.
Also, the way the medium of film works, it is very difficult to maintain characters not knowing information that is known to the audience. The audience will assume that everyone knows what they know unless told otherwise, and characters who do not know the information that is known to the audience will appear foolish and uninformed. So, if there is something that no one on screen knows...then it is best to keep that information unknown to the audience as well. If we wanted some aspect of Beren and Lúthien's story to be unknown to a particular character, we would have to go out of our way to establish that this character is ignorant of that detail.
As an example, in
Silo (an adaptation of the novel
Wool), there is a question about what the landscape outside the silo looks like. There are cameras involved, so is what you are seeing real, or is it an illusion? And if more than one possible vision is presented...which one is the real one? There is a character, early in the show, who has a chance to observe with their own eyes (no cameras/screens), so we know that what that person sees is reality. The viewer...does not see what they see. That was a very important choice; it was IMPERATIVE that the audience not know what that character saw at that time. Because if the audience had seen, all further speculation on the part of other characters would be boring, and anyone who was wrong about what was really going on would be clearly shown to be foolish. But if the audience remains ignorant, and does not know any more than the characters...the question remains open and interesting. The audience needs to discover reality with the point of view character, not a moment ahead, for the story to work.
If we have a reason to establish that a character is ignorant of the major events of their lifetime, we can do so. Tuor is a good example - based on how he was raised, he's limited in his knowledge of the world. But he's not wholly ignorant. We have to be very careful about what gaps we want to give him in his knowledge, and how that will matter for particular scenes.
