Replayed the story of Aquors. It seems this happened before Aquors since there is a notification when replaying the story. Also, someone pointed it out already. https://www.facebook.com/OrderOfTheGBFKnight/posts/427463627977100?__xts__%5B0%5D=68.ARDmYCSIGF5yjkCN8yvywQBd1Z82mWVuY8ySFHPhrUSo0hB5slVzI9lSghZnliI1XpF-lR6rscwRGwdQliTnI47KwX3kC8YuG73CMEGOcgSuKoXfEaKem57qB3sL9C8IywrNasA6z4-20ibLwyU208RjWg9dQgkYyPY_TBlIzAWkw2XSf7lmQck7-vfrZWRHRQcoivcT9sMF8ZBXtxnEOPGFw1mgW2fS0mSbRloDbL2ozDfdRaIPNWEh-2x1V180MXzKSEAjwxb-ycuUtjf42RTB3N-9PJwvACbQgCOz7UKE9ly44LuTK_XJpz2-9lb13d0PYMN011ddzT3fUthYYV8&__tn__=-R
Talk:Love Live! Door to the Skies
Yes, Muse were mentioned at the end of the original Aqours event, even before this event came out. For eagle-eyed viewers who caught that, the fact that this is a prequel was a foregone conclusion.
Apparently if you complete the muse love live event and play the aquors side story event now, the story changes a little and mentions your experience with muse within the city