See above. I think the closest Quenya equivalent to “must not” here would be volitional prohibitive vá, so I’d say Vá þoryuvan(ye) “I shall not/will not/must not fear.”
Missing the definite article here, so Þosse i órinehtar (ná). I’ll honor your choice of óre, but I do think the closer Elvish match to Herbert’s “mind” in the Litany is indo.
- Þossë nihtaqualmë nin, tyaren nancarinqua
This reads “Fear bit-death-agony for-me, cause-I destroyful.” I’d recommend the adjective nitya (“little, small”) and the noun ñuru (“death” as an abstract). Tyar- is a good choice but misconjugated, and -inqua doesn’t attach to verbal stems. We could revise this to Þosse i nitya-ñuru (ná) i tyare aqua nancarme “Fear (is) the little-death that causes complete undoing/destruction.”
Termar- is intransitive “stand, endure, last” (lit. “through-abide”); for “face, confront,” I’d recommend tenta- “be directed toward” or tar- “stand” with the allative: Tentuvan(ye) þossenya “I-will-face my-fear” or Taruvan(ye) þossenyanna “I-will-stand against-my-fear.”
- Lavuvan sa lahta nin, ar tere nin
Here’s an instance where I think Quenya would be very inclined to append the object as well as the subject: lavuva-n sa > lavuva-nye-s. Nin is dative “to/for me”; the object of infinitive lahta and preposition ter would likely be nominative-accusative ni, though I think we need another verb here for the sense of “pass/move through” to resolve the semantic friction of !lahta ter: Lavuvanyes lahta (ni) ar termene ni “I-will-allow-it to-pass-over (me) and move-through me.”
In the instance of yá avánie, the perfect augment would be more likely to elide than the long vowel of yá (WJ:366). Additionally, we’d see a subject suffix rather than an independent pronoun here, so ar yá vánies. (I don’t think auta- is quite the right verb for “go past, pass by” and would use men- myself.)
- queruvan i órë, cenuva i lomentierya
Cen- should take a dative gerund here for the sense of “in order to see,” and lomentie is the parting of journey-paths, the opposite of omentie, the junction of the directions of two people. Mentie or just tie are probably more appropriate here: Queruvan i óre cenien (men)tierya “I will turn the óre to-see its-path.”
- Þossë i avánie, nauva sinome umuntiéva
This reads “Fear that has-passed, will-be here have-nothinged.” The first half doesn’t reflect the relativity of the original, and Tolkien abandoned the stative (umuntiéva) in later writings as the “be” root ceased to be √YĒ. I’d say Yanna/ainomenna eménie i þosse, munta euva “Where/wherever the fear has gone, nothing shall-exist.”
I’d say Inye rie lemyuva or …termaruva — lemya- almost certainly wouldn’t preserve -a in its future inflection. Without the free-standing emphatic pronoun, rie seems to be modifying the action of the verb over its agent; the comparable difference in English would be something like “Only I, I alone, will remain” vs. “I will remain and remain only, do nothing else.”
Again, lovely work, and thanks again for sharing!