So we're stuck with killing off a Feanorian wife.

MithLuin and I both
suggest using Caranthir's wife intead of Curufin's.
Minor characters to cast:
Annael
Ecthelion
Glorfindel
'Rog' (
suggestions for renaming him here)
Celeborn's sister (Faenoron? Galadlas? Galadlos? Celeblos?) among the Green-elves
Meril (Orodreth's fiancé/wife), one day to be Besan of Dorthonion > Minas Tirith
Edhellos/Angrod's wife, scholar?, very briefly the Besan of Dorthonion
Caranthir's or Curufin's wife (Pennor = Quennar?) chief healer, scholar/loremaster, and artisan
Maybe minor characters now, maybe background characters (not cast) until a later season:
Maglor's wife (Faniel?) Fëanorian Besan and scholar, maybe a healer too (to replace Caranthir/Curufin's wife as Fëanorian chief healer)
Fingolfin's Besan and chief healer (Lalwen daughter of Irimë, mother or sister of Glorfindel)
Fingolfin's herald (Erien?)
Galadhon or Celeborn’s mother (name) (likely only needed in 2 episodes, maybe don’t need to name mom yet)
Galathil (likely only needed in 2 episodes)
chief of the exiled Houseless Dwarves (Mîm the I? Nîm? unnamed?)
Inglor?? (Follower of Finrod and father of Gildor. It would be cool to include him and then send him to Tol-in-Gaurhoth in Season 6. Give Finrod somebody to talk to in Nargothrond, although we could use Edrahil instead. Maybe not introduced until Season 5.)