We have not yet discussed how we intend to handle the lords of Gondolin. We know we want Glorfindel and Ecthelion. And we've discussed how Rog will come to Gondolin post-battle (so, his house is not one of the 'original' houses but a later addition, as are several others).
Houses of Gondolin:
House of the King: Turgon
House of the Heavenly Arch: Egalmoth
House of the Tree: Galdor
House of the Golden Flower: Glorfindel
House of the Fountain: Ecthelion
House of the Swallow: Duilin
House of the Harp: Salgant
House of the Mole: Maeglin
House of the Pillar: Penlod
House of the Tower of Snow: (also) Penlod
House of the Wing: Tuor
House of the Hammer of Wrath: Rog
As you can see, some of these are later additions. At the founding of Gondolin, we will only have:
House of the King: Turgon
House of the Heavenly Arch: Egalmoth
House of the Tree: Galdor
House of the Golden Flower: Glorfindel
House of the Fountain: Ecthelion
House of the Swallow: Duilin
House of the Harp: Salgant
House of the Pillar: Penlod
House of the Tower of Snow: (also) Penlod
In Season 4, we only intend to introduce Glorfindel and Ecthelion. The names in italics are there, but as unnamed faces in the background. More of a costuming choice than a casting choice, at this point in time. We'll spend a lot of time in Gondolin over the next few seasons, so it's quite possible that we'll find opportunities to give some of those unnamed lords roles or lines or character development. Or....they might just be Turgon's court, known by their heraldry and that is all.
Is this the same Galdor? That's a choice we can make this season. It
could be, though it doesn't have to be. Galdor-of-the-Havens was one of Círdan's mariners in Season 3; he's not currently with Círdan in the north, but with the people of the Havens who are currently refugees.
We know that some Sindar (including Falathrim from the [destroyed] Havens) will join Turgon in Nevrast. We will show that in Episode 4-5, presumably. These Sindar will then go to Gondolin with Turgon this season (that move will happen after the Kinslaying reveal, so it might not be automatic, but Turgon will handle it in some way).
In the
Lost Tales version of the Fall of Gondolin (the only one we have!), a lot of the folk of the House of the Tree (Galdor's house) escape with Tuor and join the refugees at the Havens of Sirion.
So, if we
wanted him to be the same person, he could wind up back at the Havens that way, and we'd have to have him stay with Círdan rather than sail west, sticking around for the Second and Third Ages.
When Tolkien was considering the 'two Glorfindels' problem, he ultimately concluded that these two Galdors were in fact different elves, but it was a question worth asking to him. He concluded that it's a common name, and it's just two random elves who happen to share a name. We could merge them, but we don't have to. If we did merge them into one, we would likely solve the problem Tolkien saw with making them a single character; in our version, Galdor is one of the Falathrim, not a Noldo elf, so there's no reason for him to return to Tol Eressëa with the other Noldor at the end of the First Age. Having one of the Lords of Gondolin be a Sinda would be an interesting choice; we could do something with that.
We're eliminating the name 'Legolas Greenleaf' as an elf of Gondolin because we're reserving that for the main character in
Lord of the Rings. We have enough other elves in Gondolin; we don't need him. Can someone else take his role? Sure, no problem. But we're not using that name.
If Galdor-of-the-Havens *is* Galdor-of-Gondolin, then that would give us interesting opportunities for dialogue between Galdor and Glorfindel later.
In conclusion - Egalmoth, Duilin, Salgant, and Penlod will not be introduced by name this season. If Galdor is a different elf, he won't be introduced, either. If it's the same Galdor, we will have to get him to Nevrast and make him the leader of a group of Sindar there.