I'm also surprised my wild guess caught on the way it did, to be fair, and originally only threw it out there so someone could point out some obvious feature I missed that ruled it out entirely. That hasn't happened yet, to my surprise, aside from a few recent "it can't be because it can't" arguments that don't actually have any basis. Yes, he said he'd watch over the Tower until the world was ready, but we also promised we'd make that world and see him again, a promise not unlike the one Minfilia is now confirmed to be keeping.
Also, while I did sketch in eye marks for the sake of clarity, they are present in the original image, unless you can propose an alternate explanation for the jagged edge to the shadowing around the right eye, with something more conclusive than the racial markings exhibited by the race that normally has access to that facial type, that would normally be present in that exact shape at that exact spot on the face. And, again, the mouth, chin and nose are a match, as near as I can tell, and I did go through quite a few screenshots from a number of angles before publishing that conclusion.
But it could be more misdirection. He could simply be a character who switches facial models completely when the halfmask comes off, like Lyse, or Elidibus, and the use of G'raha's facial presets is either a coincidence or a prank. I'm prepared to be wrong entirely, of course, but for now I don't see the harm in allowing speculation to continue, especially as (for once) I'm barely involved in it.