Great job on the lyrics! They convey the meaning of the song beautifully by drawing on the nuances of the Japanese language. To me, the music works better with the rhythm of Japanese speech. I think my favourite line in this version is “Akari, kasumi, hibiki subete no odori”. A few deft brushstrokes that capture the full scene.
A few observations:
Shizukesa ga ooku ni naru kono yoru ni
Be careful with the pronunciation of ooku. The “o” needs to be drawn out. Otherwise, it sounds more like oku.
Taiyou ni oogoe dasu
I think what you want to say here is, “Raise your voice to the sun”, in line with the original lyrics. If so, then the imperative “dase” may be more appropriate.
Onegai no ARIA wa shizuka ni naiteiru
I find that this line has too many syllables for that part of the song (the same for the original lyrics). One suggestion: “koinegau ARIA wa odayaka ni uraeru (or itamu)”. I’d ask a native speaker for the best choice of synonym.
Yami wa kodokuna uta wo utatteiru
How about “yami wa sabishiku utatteiru”? Avoids the repetition of “uta”, though it may make it more difficult to match the music.
Hope this helps. I’m looking forward to the final version!
Edit: Bah, it wouldn’t post all that Japanese text. Romaji it is.
