The month after Witrosa is Scholus, since most of Era 4 happened on the 24th of Witrosa I guess we could say the Stranger needed ~a week to finish his work and the festival is in the first week of Scholus.
Talking about the calendar, in this timeline the TUBA reveal would probably be far less important than in the current one, definitely not enough to be the year 1 and day 1 of the calendar; it would make more sense to put the day Mac ask Voidus to seal the alleys in that place
That work for me
(by midnight she means the midnight between the 14th and 15th)