Neru’s mansion being the Redd Manor? That… could be true.
From what I can recall from the story, it’s been a while since I read it so do take this with a grain of salt, the Redd Manor has only been used sparely throughout the story, but the little times we get information about it are from Neru and Nomino. Neru’s description while holding on to the Redd Manor’s files makes it seem that his house isn’t the Redd Manor, but this could be due to him losing memories of it or even not knowing about it. The other descriptions come from Nomino where he talks about a red mansion in a world with blue skies, which is kinda the opposite of what currently Neru’s house is. It could be that the Neru’s house was the Redd Manor back in the day but after some events, it was abandoned or changed to what it is now. (Or it could just be another mansion that happens to be red.)
And speaking of time, I’ve never considered that the story could have time shenanigans… as in maybe time-traveling? It could explain some things, like how Nomino seems to know how everything goes during the War, and even the slip of paper Shax got during his pickup of delivery could be a message from the future. (And yes, I still think that the message is important to the story and that it would be brought up later in the story… eventually.)