Seems like its going to be a dead game for a month. Real Walpurgis Night is April 30th/May 1st which is wed/thurs and they'll probably try to line up the WN Banner with that. That would maybe put the next Canto on either the second or the third week of May depending if they want to launch it while WN is running.
This seems like the most likely scenario. Every Walpi after the 2nd has been released roughly 126 days apart and lasts 2 weeks. This, along with season getting previews the Friday a week before release (i.e. Season 5 teaser came out on Sept. 27, Season 5 came out Oct. 10th), and that seasons get 3 weeks of story, means that if we don't get the teaser this Friday we won't be getting Season 6 until after Walpi 6. Thus I can foresee several scenarios:
A: We get the trailer this Friday, we get Canto VIII from 4/24 through 5/8, and Walpi 6 on 5/15
While this has precedent, I find it unlikely. Having Canto and Walpi back to back wold be a cramped schedule.
B: We get filler banners on 4/17 & 5/1, Walpi 6 on 5/15, and Canto VIII on 5/29
Keeps the schedule, but leaves April a dead month.
C: We get Walpi 6 during Canto VIII
Not impossible, but I find it unlikely.
D: Filler banner on 4/17, Walpi 6 on 5/1 and Canto VIII on 5/15 (ProfDong's Scenario)
Having Walpi at the end of April would help keep it from being a completely dead month.
