Regarding the Glittergaze castle's:
It was in an online article and not within a direct developer quotation. The journalist nestled the info into a paragraph about the ice world. What they wrote was something to the effect of "you can also go inside these castles, but Playtonic are not ready to discuss this current." (A loose recollection, but that's the essence.)
This info stood out to me because it was a rare instance of truly *new* info, hidden in swaths of interviews and impressions that were largely repetitious (also why I could not find the source.)
Well. Someone else verified they read it too, at least.