I've spent the past few hours sifting through the evidence, including the OP, the thread, the cases provided by Galens and Sevil, and my own research into PoC and its systems/lore. These are my conclusions.
A large portion of this evidence, including the language used in the scans, the unusual nature of the lore provided, and the oddities in the developer responses are pieces of evidence I consider compelling, but not conclusive. On the basis of these pieces of evidence, I would be willing to remove the scans from all DMC indexing, but I would not be willing to take action against Galens - the former only requires establishing the evidence isn't verifiable, the latter requires establishing unquestionably that Galens fabricated the scans, two very different levels of evidence.
However, there is one piece of evidence that I believe conclusively establishes this case, which is the discrepancy in the footage provided by Galens. I have checked through the footage by Galens, as well as the alternate footage provided in the OP, and footage of the game from several other channels on YouTube - all frame-by-frame, and all cross-referenced thoroughly. In every single piece of footage I have identified that was not recorded by Galens, I can confirm that the artwork on the loading screen does not pop in until a minimum of several frames into the loading screen; there is always an intermediary period in which the loading screen has appeared and the artwork has not loaded in yet. Always, with the one exception of Galens' footage with the scan on the loading screen.
Galens' prior argument, that this was due to stuttering in his game, does not work either. For one, I can find no other discrepancies in Galens' loading screen footage to suggest the game was stuttering during the loading period - the loading screen includes the animation of the neon light flickering, and I can find no sign at all that this animation is lagging or skipping frames. Secondly, in the alternate footage I've found, there have been numerous examples of videos of the game that evidently stutter far more than Galens' footage does, and none of them ever result in skipping the first few frames of the loading screen. Thirdly, if it was even hypothetically possible for frame skipping to occur on the loading screen to produce this effect, I would naturally be expected to have found it at least once by chance - yet, with dozens of examples, I can consistently identify that nothing even remotely similar has occurred.
The reason why I believe this evidence conclusively establishes the case against Galens where others do not is because, as far as I can tell, there are no reasonable alternate explanations for this discrepancy beyond what has been proposed in the OP - namely, that the footage has been doctored. Alternate explanations may exist for, say, the suspicious use of language in a scan; but in these circumstances, I don't believe there is any alternate explanation for the discrepancy we observe in the footage. As Galens has already clearly expressed the fact that they were the one who played the game in this footage and recorded it, there is furthermore no person who could have reasonably been responsible for doctoring this footage other than Galens. If this logic holds, then it establishes that Galens doctored footage to falsify the existence of scans which they were then responsible for indexing on the wiki.
As I have stated, and will reiterate here, I wish to give as much opportunity as possible to Galens and the other opposition to defend their case. If this deduction can be proven to be invalid - for example, by proving that there was a reasonable alternate explanation for the discrepancy, or that there is another person who could have reasonably doctored the footage - then I will give your argument my analysis and reconsider the case with the factors you have acknowledged. At present, however, I see no reason to deny the notion that Galens doctored the footage for the purpose of falsifying scans that they used for indexing on the wiki, and I would therefore support a permanent ban.