I had to watch some bits of the shadow of the arkguard to remember lol I think to remember that at some point in Episode 2, either because the ones talking were illiterate or something (was it Tonnio? can't remember), but the player had more info of the real history of Gurhal than the actual characters, they didn't even know the races where human engineered. Of course the illuminus would explain this in their supremacist way, and Lunz way of explaining is also off from the previously known official history of Guthal, where only the existence of the ruins and the confinement system point to an ancient civilisation, speculating they came from the starts instead of being native to Parum is quite an imagination on his part. But then of course, the symbols on the ruins make us remember of the espers in Algol, the same way as the Muut Dits Poumn in PSO, we could still establish the ancients are from Algolian origin. But I completely forgot what that Pioneer lookalike was in Infinity...

The Xenoblade 2 DLC is fanservice indeed, as stated by the Nopon Sage himself lol the case of Elma is exactly the same as the Persona Dancing games "you are dreaming, you will forget everything it's happening there, so just dance!" but just sticking to the main story it's obvious there are connections I won't detail since they are hard spoilers, and XCX on its own talks at least about an ancient civilization that came from another universe and dominated the galaxies around (then there is the fan speculation that Mira is the Bionis / Mechonis world, AND provably in a different dimension than X intro (which MAY be xenogears universe), since even Time Travellers can't escape, AND provably the origin of the ancient civilization, which would make Shulk and Elma be in the same world, but extremely separated in time, but that's not a problem for the Nopon Sage).