I think this actually makes it rather doubtful wether these scenes are actually true tbh.
Thereās something that kinda got sidetracked in Umineko. When we first saw Angeās future in 1998 at the end of arc3, the scenes with Bernkastel clearly suggests that this future is āmerely one probably futureā with a rather low probability, but not the necessary factual future. If this is truly the future then itās not merely a probability of a future, itās just the future and thatās how it ends.
In arc4 meanwhile LD tells Ange that itās not impossible for Battler to leave Rokkenjima in 1986 and come back home, but that will be for an Ange, that is, essentially, of another timeline. It will never be for āthe Angeā that she is talking to.
I donāt really know what really happened there, it kinda sounds to me like something Ryuukishi discarded midway or something, but at the very least thereās nothing that really makes it certain that what weāre seeing is the future, and even if this is essentially ācorrectā (as in, Eva did really come back, and so the at least official events would be true) we basically know from this line of thought that every scene after the skyscrapper incident are fiction, and same for the entire scenes of Ange and Featherine in arc6. This kinda strongly suggests that these scenes are fiction as well, and Iām not sure why that wouldnāt apply to the school scenes of Ange.
It may be even more lonely to think of it that way, but as a result I see nothing that truly ascertain that Ange ever had Mariaās diary.
Everything about prime is so confusing, we really have almost no information on what could be true and what couldnāt. In the arc7 TP, Bernkastel summoned Ange and Lion to the same theater room thing to essentially torture them (letās leave it at that), which may be me reading too much into thisā¦ but they have essentially a strong connection : They are both characters introduced by Bernkastel as only existing in fragments that have very low probability of occurring, just that Lionās has a ridiculously lower probability of occurring.
A thing I could add is that Angeās ādeathā in 1998 is part of an endgame scroll, which kinda shows that Angeās future is part of a fiction.
Iām not really sure what to conclude there, because at the very least I want to believe that the very final scene of arc8 is actually true (that Ange became a writer) but I also canāt shake out the idea that itās aā¦ kinda weird thing. (Ikuko never aged, and the description seems to suggest that Tohya is now younger then the current Ange).
Ultimately tho, it comes down to this, I donāt think we have any reason to believe that Angeās world that we see is actually anything but a fiction. I also donāt think we can be certain that the actual future is a fiction either. Itād be essentially the same as the āstory arcsā vs āwhat really happened on Rokkenjimaā. That is, saying that something actually did happen does not mean that any of the message bottles contains anything about the truth of what really happened.
And so that was a long turnaround, but I would say that itās extremely unlikely that Ange actually had access to that diary.