It took me all day to find this, but per Yanaxx's wishes, I am disclosing the information here. Originally, I found this information via a Reddit post (https://www.reddit.com/r/Deathloop/comments/pqc06b/deathloop_lore_explanation_and_theories/) discussing the Pre-Loop history of Deathloop, and how it tied into the Dishonored universe beyond the pistols and Drunken Whaler song. Through contact with one of the individuals involved in the original post, whom I am leaving anonymous, I discovered that the origin of these slides came from the blog, more specifically their portfolio, of the original Narrative Lead of Deathloop: Sandra Sachka Duval.
As it can be seen here, the so-called leaked presentation and the presentation on Sandra's portfolio are one and the same, although they are somewhat dated. That said, I bring all this up due to the sole point of contention myself and Yanaxx have reached in this presentation. Before, there was little to no evidence of its legitimacy or if it was simply a hoax. Now I have definitively proven that it is not only legitimate, but comes directly from a former Arkane employee, who happened to be the lead narrative designer of the game.
The question I ask now is what the wiki or greater Dishonored community is to make of this information in wiki terms. No longer is this some potential hoax or elaborate fan theory, this is direct confirmation from the original narrative designer of the game. I personally maintain, as I did with the original presentation on Reddit, that this information is to be displayed on the wiki for both insight into what the narrative of the game was during its development, and what aspects it clarifies or otherwise expands on that did or did not make it to the released version.