Just dropping some sketches of me thinking a bit about the treehouse/huorn escape scene. These are not my "finished concept art" ideas, this is just in a way visual brainstorming.
first up I'm wondering about the design of the tree, the first thing that came to my mind was a rather treebeard-ish tree like this, but with a big crown that sort of closes into a cage. I think there maybe could sth a bit less obious and not just a direct reuse of the lotr-ents.
I was also wondering how to depict the weaving of the cloak, i feel like i see to variants at the moment: Luthien very animatedly singing and maybe dancing in an moving cloud, almost tornado of hair, which then weaves itself, or a much quieter scene where in the dark of the treehouse (/treehouse-like huorn luthien enclosure) luthiens hair just greeps growing until she sits in a pile of hair that then magically starts weaving itself, she maybe softly sings along, or not at all. I think the first is sort of the magical anime transformation scene that would be expected, but the second one could be very cool i think.
... and then i did some pretty luthien drawings, bc as we established, nobody's immune to the charm. But otherwise, mostly just a little note to the costume/styling department from my side xD. i imagine the "cloak" more as a big sheet of maybe sort of greyish art-nouveau camouflage fabric that she wraps herself in, less a "finished cloak"

and some thoughts about the escape, i think the most basic thing is to have "just" a rapunzel where she lets herself down by her hair, i could also imagine her maybe putting some guards to sleep, maybe foreshadowing her battle against morgoth a little ( which would make the first and the last song spell of hers being a sleep spell

)
And the most, let's say, involved option i can imagine is one where there might be a little of a chase through the woods, an almost bilbo v mirkwood spiders scene, but luthien could almost like a spider restrain ppl or trap them, and then get away. I know this is very likely "too much" for that scene, but i just got the idea because i imagine Luthien also being a bit wild, maybe eerie sometimes (mononoke-ish) and not only a classical tralalalolly elf, and if i were to make a mononoke style lay of leithian anime, it might very likely go this way xD
But yeah, just brainstormings.