Okay, I've figured out 99%, if not 100%, of the text in the opening and... it is basically the epitaph in FRENCH. However, the thing is... that's arguably not a very good french. Although most of the lines grammar isn't that awful, the terms used make the whole thing hilarious.
Spoiler for Original French Text and its translation:
[General Note: the articles used are intended to be exactly like that if you were to read these in French. So the distinction between "a/an" and "the" isn't random in my translation]
La personne est partie dans la deuxieme larme du soir en deux personnes pour se blottir.
The person has gone in the second tear of the night into two persons to hug.
[Note: the English verb "to tear" was probably mistaken for the lacrymal drop... as Larme = Tear (from crying, of course). It appears to me that they translated the epitaph from Japanese into Engrish, then translated that mangled Engrish into even more mangled French... or Flench I would say...]
La personne est partie dans le troisième eloge du soir mon nom que l'honneur est haut dans.
The person has gone in the third oration of the night my name that honor is high in.
[Note: the structure in French is much worse than it might look like in English. The "that" has no meaning here whatsoever. High is as in height]
Le quatrième soir... gâtez un cerveau.
The fourth night... spoil a brain.
[Note: "to spoil" with its meaning as in... spoiling a kid. Very likely they used the "ruining" definition of the verb "to spoil", but when you go through English to French with that verb, you mostly get the context of a dotted kid. It also has a definition of "damaging" like its English counterpart, but that isn't really its primary meaning when you use that verb in French. Don't ask me why they used "brain" though...]
Le cinquième soir...gâtez le coeur.
The fifth night... spoil the heart.
Le sixième soir... gâtez l'esprit.
The sixth night... spoil the spirit.
[Note: Another proof it is from English. They most likely translated the sixth with "Guts". And Guts can be considered from the "force of will" perspective, thus spirit.]
Le septième soir... gâtez un genou.
The seventh night... spoil a knee.
Le huitième soir... gatez les moyens de transport.
The eighth night... spoil the means of conveyance.
[Note: no, I'm not doing any mistake here. That literally implies car, bicycle, etc]
Le neuvième soir, le magicien ranime et personne ne peut survivre.
The ninth night, the magician reanimates and no one can survive.
[Note: Magicien (Magician) in French is used for a man using magic, it cannot be used for a woman (for a woman, it would have been "Magicienne". That is still a far cry from Sorcière (witch)). And yes, the way how the verb "to reanimate" was used is definitely made so it is "the magician" that performs the "reanimates". Looks like Beato became a first aid nurse but utterly fails...]
Le dixième soir, le voyage est sur et atteindra le volost d'or.
The tenth night, the jouney is safe and will reach the golden volost.
[Note: Volost is... supposed to be a Russian peasant community...]
Le magicien loue un sage et accordera quatre trésor.
The magician praises a wise and shall bestow four treasure.
[Note: trésor (treasure) is in its singular form, not plural]
Tout l'or du volost d'or comme pour un.
All of the gold of the golden volost like for one.
[Note: comme (like) is used as a comparative statement. it seems they put the "One shall be" at the end and completely turned it into something... weird.]
Un revivifies l'âme de tous les gens morts.
One revivifies the soul of all of the dead people.
[Note: Revivify verb is really not a common word in French, as much as in English. The tense is meant to be used in present here.]
Un revivifies même l'amour que j'ai perdu.
One revivifies even the love I've lost.
On laissera un magicien s'endormir à jamais.
We shall let a magician sleep forever.
[Note: Magician is still in male form... "On" is a personal pronoun in French that is extremely vague in term of numbers (can both mean singular and plural) and also doesn't define if it is either the first, second or third person. In general, it is used as a "we" or "one".]
Dormez paisiblement ma plus chère magicien Béatrice.
Sleep peacefully my more dear magician Beatrice.
[Note: "my more dear" is intended to be incorrect, especially the "more". "my more dear" in French was actually appropriately put in female form, but magician is still in male form here]
[Note: for some reason, there is a japanese line in the lot, in romaji]
Anmari ganbatte Tékisuto no kaiséki shinaidé né.
Don't waste your time trying to read this text, ok?
[Note, part deux: it seems Ryukishi saw me coming...]
It doesn't seem there is a translation for the first twilight or anything prior that.
Also, please note they actually went as far as putting the -accent- correctly, although it seems it was a mess for them, so all the letters with an accent are... in arial for the font
That mess raises one major question though: why is it in French...?
Umineko involved it barely (only one major mention: Mariage Sorcière), so translating the epitaph into French instead of... say Italian is quite weird to say the least.