Actually, I have the list of musics matched with their filenames that I compiled a while ago for something else. Here:
=======================================
Higurashi no Naku Koroni
file name = track name (All tracks located in the "LP" folder)
1.MP3 = パリの午後
2.MP3 = Hello!
3.MP3 = スタコラサッサ
4.MP3 = Digital Network
Rena.mp3 = Lunch Time
Mion.mp3 = Spring Step
Satoko.mp3 = Small Town
Rika.mp3 = Baby's Walk
5.MP3 = オレンジ色の詩
Tip.WAV = 朝露
6.MP3 = Silence
9.MP3 = 静寂
Higurasi.wav = ひぐらしの声
RAINY.MP3 = Rainy Days
GIWAKU2.MP3 = Silver Mirror
7.MP3 = 洞窟
8.MP3 = 魔族研究所
FASCISM.MP3 = Fascism
GEAR.MP3 = Gear
DAWN.MP3 = Dawn
MDS2.MP3 = Theme of Owner
DANCERS1.MP3 = Dancers1
DANCERS7.MP3 = Dancers7
SNOW3.MP3 = Snow3
SNOW4.MP3 = Snow4
SUNRISE.MP3 = Sunrise
Tell a thing.mp3 = Tell a Thing
LIE.MP3 = Lie lies - Lies lie
LOOP131.WAV = Loop131
CHILD3.MP3 = Days of Children3
DANCERS5.MP3 = Dancers5
heigen2gm.mp3 = 平原を行く
MED1.MP3 = Meditation1
file name = track name (All tracks located in the "minigame" folder)
BGM05.MP3 = お手伝い☆
A5_06198.MP3 = 迫り来る危機
BGM02.MP3 = 襲撃！
A7_06056.MP3 = 逃出
BG01002A.MP3 = 勝利！
FOLDED.MP3 = オラオラ 【Folded】
VOICES.MP3 = リタイヤ【Voices】
=======================================
Higurashi no Naku Koroni Kai
file name = track name (second name) / artist (All tracks located in the "LP" folder)
T1.MP3 = Thanks / dai
IRU.MP3 = Iru / dai
Cafe.mp3 = 風車小屋の少年 (喫茶店みたい -Cafe-) / ゆうね@柏餅
Z2_hig3.mp3 = Daily Passing By (d_p_by) / zts
Z2_HIG2.MP3 = What is Wished / zts
demo(48kHz).mp3 = 陰 (かげ) / dai
OMAKE2.MP3 = you (M. Box風アレンジ) / dai
Nazo.mp3 = 古 -いにしえ- / ゆうね@柏餅
Soul_scour.mp3 = Soul Scour / dai
IWAKANNNOHATUGA.wav = 違和感の発芽
depressive paranoia(心象音楽系).mp3 = Depressive Paranoia (d_paranoia) / tack the crow
Z2_hig1.mp3 = Soak / zts
DEADEND.MP3 = 見えぬ未来 / DJ NETA-RAW
getting_mad.mp3 = 狂気への回廊 / DJ NETA-RAW
hig_sample_kyouki.mp3 = 狂気 / モロコ
higurashi_soundscape.mp3.mp3 = 祝祭 (Soundscape ver.) / カレギュウ (oi)
Hgrs01.wav = Solitude / すえばし
T2.MP3 = Confession / dai
You.mp3 = you / dai
03_CELE.MP3 = Daily Passing By (d_p_by celesta) / zts
見えない何かに怯える夜.mp3 = 見えない何かに怯える夜 -2nd Edition- / 煉獄小僧
Amber.mp3 = Amber / 朱月笛丸
bellflower.mp3 = Bellflower / 朱月笛丸
HGRS_03.MP3 = Frozen Memories / すえばし
Feel.mp3 = Feel / dai
Birth_and_death.mp3 = Birth and Death / dai
Sheep counts.mp3 = Sheep Counts / Propan Mode
higurashi(Utu).mp3 = 鬱 / 海老スパ
PROS.MP3 = Pros / Propan Mode
Cradle song.mp3 = Cradle Song / dai
SORA-YUME-.mp3 = 空夢 / dai
彷徨いの言葉は天に導かれ.mp3 = 彷徨いの言葉は天に導かれ / 煉獄小僧
ZERO.MP3 = Z・E・R・O / 煉獄小僧
It moves.mp3 = Nearsightness to Parallel -鼓動- / pre-holder@137
INSTICT.MP3 = Nearsightness to Parallel -胎動- / pre-holder@137
r of can.mp3 = R of Can / Propan Mode
BIGBEAR.MP3 = Bigbear / 朱月笛丸
Fearlessnessl_E.mp3 = Fearlessness / dai
Gray_2.mp3 = Gray / dai
白霧の頂～Blanc_pur～Ver.β.mp3 = 白霧の頂～Blanc pur～Ver.β / 風域
OMAKE_01.MP3 = Cross Examination / dai
liveシーン音楽.mp3 = Conviction / dai
HITOE_2.MP3 = 一重 / dai
LIVE_2.MP3 = LIVE / dai
Typewriter.mp3 = 虚 / dai
chants90-AHH.mp3 = Requiem for the Disaster / DJ NETA-RAW
月（惨⇔賛）歌.mp3 = 月（惨⇔賛）歌 / 風域
=======================================
(I listed my own favorite tracks in bold
)
It looks like Ryukishi07 had some sort of "file name jumble system" where he would toss the files in and get back some messed up file names. ^^;
Now, "Higurashi no
Naku Koroni" (question chapters) only featured non-licensed free musics tracks, but there were some really nice ones in there. In any case, since you can
download the trial version of the game (featuring the entire first chapter, Onikakushi-hen) from the official site. You'll probably find most of the tracks from the question chapters (most were used during Onikakushi) included in the trial version.
But the quality of the game's music really took off when we entered into "Higurashi no
Naku Koroni Kai" (answer chapters), with bgms created by skilled doujin artists. In particular, artists like
dai with his wonderful piano tracks, or the "thinking musics" from Propan Mode (I loved Sheep Counts
), to the exciting adrenaline rush from 煉獄小僧's tracks (彷徨いの言葉は天に導かれ and Z・E・R・O made Tsumihoroboshi-hen's ending one of my favorites). The story of Higurashi wouldn't have half the impacts it did if it weren't for these musics.
EDIT: Eh? The trial version link isn't working. Well, give it a try later. ^^;