It is important to remember that in a television show, only those characters with speaking roles have names. These family trees are trimmed down on purpose, not by accident. Should we wish for more characters with speaking roles, we can add them to the family tree in later seasons. But it is important to keep in mind that teaching the audience every name on the family tree is not a goal of Silm Film. Rather, the goal is to develop stories for a representative number of characters, and focus on telling the audience those stories. Other stories may exist in the background, but we aren't going to tell them all.
We have not yet determined how much of, say the Wanderings of Húrin or Concerning the Hoard will end up in Silm Film. That is a question for a later season. If we need a speaking role, we will likely take the name for the character from a family tree or from one of those sources, but we are by no means committed to including all of Tolkien's named characters in this portion of the story.
As for why it is undesirable to portray Beldis as 20-30 years older than her husband? Corey Olsen is already of the opinion that Tolkien has his characters marry later than we would expect for their cultures. Theodred, Eomer, Eowyn, Boromir, and Faramir all being unmarried at the time of the War of the Ring seems unusual and even irresponsible. Indeed, two of them die in the war, leaving no heirs, and two are wounded grievously, at risk of dying. The future of Gondor and Rohan's rulers is in question....but if they had simply married younger and had some kids, the future of their house would be less uncertain. Knowing that Corey Olsen feels this way about these stories, it seems very unlikely that he would support inventing a story to insert into Silm Film where a human character who is the heir to leadership of a house would deliberately marry a woman a generation older than himself who could be considered past childbearing age. I am not suggesting that we can't come up with a story as to why that might happen - I am saying we don't want to!
I agree that Tolkien often tried to retcon any discrepency in what he had written - IF it had been prepared for publication and the anomoly slipped through in that process. He considered himself committed to the published versions of his story (in most cases - there is the case of the 1st and 2nd editions of the Hobbit, in which he retconned the change). But Tolkien was quite comfortable striking material out of his drafts and correcting it as he made changes to stories and names, etc. And simple errors have also been changed in the published version of The Lord of the Rings. Had this age discrepency been brought to his attention, chances are he would have added a generation to the family tree to correct it. He was very careful to make ages and years work out in his geneologies, so that no one is having children at improbable ages in all other cases - this seems an error, not a deliberate choice to make a 50+ year old woman become a mother! Certainly, others may interpret the text otherwise, but I think it must be a mistake.
Our step back in time in Season 7 is for the express purpose of telling the story of Húrin, Huor, and Handir in Gondolin. We are not telling other stories in Beleriand during this 'overlap' timeline, as they have already been told in Season 6. We will let our audience know that this is a step back in time by showing the tower at Tol Sirion still standing and inhabited by Sauron's forces. The audience knows Lúthien brought that tower down, so that will help them orient to when in the story we are. Also, while our characters are in Gondolin, we will have them look up and see the eagles carrying Beren and Lúthien overhead. We showed the view from Lúthien's perspective last season, looking down on Gondolin. So that will be a touchstone as well. Both of these (the tower, the Eagles) should appear in Episode 1, so that in Episode 2 we can move into the current timeline. The ruined tower will let the audience know that time has passed and we are 'caught up' in our timeline.
We have not yet determined how much of, say the Wanderings of Húrin or Concerning the Hoard will end up in Silm Film. That is a question for a later season. If we need a speaking role, we will likely take the name for the character from a family tree or from one of those sources, but we are by no means committed to including all of Tolkien's named characters in this portion of the story.
As for why it is undesirable to portray Beldis as 20-30 years older than her husband? Corey Olsen is already of the opinion that Tolkien has his characters marry later than we would expect for their cultures. Theodred, Eomer, Eowyn, Boromir, and Faramir all being unmarried at the time of the War of the Ring seems unusual and even irresponsible. Indeed, two of them die in the war, leaving no heirs, and two are wounded grievously, at risk of dying. The future of Gondor and Rohan's rulers is in question....but if they had simply married younger and had some kids, the future of their house would be less uncertain. Knowing that Corey Olsen feels this way about these stories, it seems very unlikely that he would support inventing a story to insert into Silm Film where a human character who is the heir to leadership of a house would deliberately marry a woman a generation older than himself who could be considered past childbearing age. I am not suggesting that we can't come up with a story as to why that might happen - I am saying we don't want to!
I agree that Tolkien often tried to retcon any discrepency in what he had written - IF it had been prepared for publication and the anomoly slipped through in that process. He considered himself committed to the published versions of his story (in most cases - there is the case of the 1st and 2nd editions of the Hobbit, in which he retconned the change). But Tolkien was quite comfortable striking material out of his drafts and correcting it as he made changes to stories and names, etc. And simple errors have also been changed in the published version of The Lord of the Rings. Had this age discrepency been brought to his attention, chances are he would have added a generation to the family tree to correct it. He was very careful to make ages and years work out in his geneologies, so that no one is having children at improbable ages in all other cases - this seems an error, not a deliberate choice to make a 50+ year old woman become a mother! Certainly, others may interpret the text otherwise, but I think it must be a mistake.
Our step back in time in Season 7 is for the express purpose of telling the story of Húrin, Huor, and Handir in Gondolin. We are not telling other stories in Beleriand during this 'overlap' timeline, as they have already been told in Season 6. We will let our audience know that this is a step back in time by showing the tower at Tol Sirion still standing and inhabited by Sauron's forces. The audience knows Lúthien brought that tower down, so that will help them orient to when in the story we are. Also, while our characters are in Gondolin, we will have them look up and see the eagles carrying Beren and Lúthien overhead. We showed the view from Lúthien's perspective last season, looking down on Gondolin. So that will be a touchstone as well. Both of these (the tower, the Eagles) should appear in Episode 1, so that in Episode 2 we can move into the current timeline. The ruined tower will let the audience know that time has passed and we are 'caught up' in our timeline.