I agree 100% that the question of 'Does Fingon have a wife?' hinges very much on 'Who is Gil-galad's father?' And that will be a question the Hosts will want to address...eventually. The only time they touched on it (and it was
briefly), it was to toy with the idea of having Gil-galad born in Valinor! In that instance, he would have been Fingon's son, but....obviously we did not follow through with that thought and the question remains up in the air.
Eldalotë's role during the Dagor Aglareb will be to act as a trojan horse under the control of Morgoth (Spell of Bottomless Dread) and do something to weaken the Noldor from attack from the orcs along the coast. Whether she opens the gates, or sends the guards away or what has not yet been figured out, but that's her role - Morgoth's puppet mole. It was also suggested that she be given some moment of lucidity later to express her deep regret over all of this, and that perhaps she'd have a moment of 'fighting off' the control to do something heroic later. In other words...she will have a story stretching from the Mereth Aderthad to the Dagor Bragollach (at which point she will likely be killed). It's not a
happy story, of course...but it is a story.
I don't see any reason for the Fëanoreans to abandon the practice of having heralds; they just use each other. Maglor is Maedhros' herald, and Curufin is Celegorm's (probably). Caranthir could ask Amras to be his, but Amras turns him down. (So maybe Caranthir just doesn't have one, so has no one to tell him he's making a bad call when Ulfang comes along). Of course, in the Fëanorean camp,
everyone is a fighter, so the idea of the herald being solely a healer is not adhered to. But, hey, someone had to teach Elrond how to be a healer, and, well, why not Maglor? (And yes, I realize it could have been someone else.)
Incorporating the role of Besan into this project is
exactly the sort of thing we should do to keep from viewing the female characters as extraneous/expendable. If we can't articulate their roles, then they are just nebulously there. If they're officially part of the court/running the household/have a quasi-religious role related to lembas...that gives us something to work with. And just as of course every kingdom needs a ruler and every commander needs a herald

, we can confidently say that every land needs a Besan.
Fingolfin's Besan is an interesting question. It was suggested that Glorfindel be Irimë or Findis' son, so he'd be Fingolfin's nephew (and Turgon's cousin). That fits him neatly into the family tree, but of course does not provide a close female relative of Fingolfin in Middle Earth. We could add an extra generation in there; Glorfindel could be the son of Findis' daughter, and maybe Findis' daughter is married to a Noldo (non-royal, obviously) and therefore came along.
So....this woman (let's call her Lalwen) would be Fingolfin's niece (as the daughter of Findis or Irimë). In the absence of his wife and daughter, she might be his 'nearest' relative and then step up into the role of Besan. This would be an interesting dynamic, because her husband would be a 'nobody' among the Noldor, but she would have an important role in Fingolfin's court. Their son Glorfindel will of course have an important role in Turgon's court. 'Lalwen' would not become prominent until after Aredhel goes to Gondolin. I realize that "Glorfindel's Mom" wasn't necessarily a character we thought we needed, but....maybe? Alternatively, she could be Glorfindel's sister (as mentioned above). Glorfindel is an adult when they cross the Helcaraxë, so this woman could be his mother or his sister (story-wise).
On the invention of original characters:
We are not forbidden from doing so, but of course any suggested original character will need to be approved before being incorporated into the story. In Season 3, we invented Norn, because it became clear that we needed a 'dwarvish ambassador' and could not just rely on the kings to talk directly to one another all the time. If an existing cast member could fulfill the role proposed for the original character, the Hosts will likely prefer to use the existing character and veto the invented character. But obviously, this is a case-by-case basis. We can propose original characters as we go; some will no doubt be vetoed.
As we have gone through this project, there have been plenty of moments when people have been eager to toss in a beloved minor character. Sometimes, the Hosts have embraced this (in the case of Rog, I think they're 100% on board), and other times they have cautiously accepted this (Rúmil of Tirion was liked as an opponent to Fëanor, but not so liked as to be a voice they wanted to hear at the final torchlit meeting in the square of Tirion). We're including Tevildo and Boldog and possibly even Fankil (though he's a mortal Man now). But while this eagerness is part of the fun, they do often warn us to cool it. We can't include everyone. One of the complaints about the
Silmarillion is that it has way too many characters to keep track of. So, given that the starting point is already a difficult cast to juggle without making characters glorified extras...what they really don't think we need is *more* characters. It's not that we *can't* introduce characters who aren't named in the published
Silmarillion. It's that sometimes they will veto these suggestions as unnecessary. So, no Argon in this project. Galadriel was the only Finarfinian introduced in Season 2. Her brothers were onscreen, but didn't have any lines. We introduced Finrod as an actual character (rather than a guy standing there in the background or cameo) during Season 3 in Araman. Given that...an extraneous Prince of the Noldor we hadn't gotten around to introducing yet and were intending to kill off as soon as he reached Middle Earth? Nope, nix, cut that. Give those lines on the Helcaraxë to a character we're trying to introduce who we can use later, like Angrod.
The nature of our story is that no character is the main character. Each character has their own story, some brief, some longer, and some vanishing for awhile and then coming back to importance later. We have a lot of people to juggle, and if you drop some, they just stand there in the background with nothing to do. We want to avoid that.
So, the objection to inventing a brother for Penlod was more 'I think we have enough named characters in Gondolin already,' and that's a valid point. That wasn't a geographical location or storyline that
needs a new invented character. Whereas in Angband or among the dwarves...we're much more likely to have a role we want to fill with a character who didn't make it into the published Silmarillion. So...if we are in a position where we
need a character to fill a role, and there's no existing character to step into that role....it seems much more likely that the Hosts would be willing to consider inventing a character in that situation.