Poor Her (rubs her head) I Hope there is a season 3 (or at least write a fanfictious one) where she finds a Boy of her dreams (Unknowingly Breaking the curse which extinguishes her existence) and thus she starts appearing regularly without fading out or excluded or other methods which blows out her presence complete with a crossover with Yuru Yuri and the 1997 blockbuster Titanic.
I have planned to write a Yuru Yuri Fanfiction where Akarin where she finds a Boy of her dreams (Unknowingly Breaking the curse which extinguishes her existence) and thus she starts appearing regularly without fading out or excluded but saved for the last episode (which literally happened).
Furthermore Kyoko started fading out (like Akarin did in seasons 1 and 2) instead that the Officers, Stewards and Deck crew on decks A to E could not find her when the ship struck an iceberg much like the Titanic thus it started sinking
There were 4448 people on board, 1420 people perished while struggling on the water surface among the perished were Kyoko, Ayano, Chitose, Chizuru, Nishigaki sensei and Rise (who did not swim to the surface to bob for air as they were drowned almost immediately when the water was 1000 times colder than ice)
While 3028 escaped on the 100 lifeboats provided which were floating nearby, only Lifeboat#1 where Akarin's boyfriend, his mother and the surviving ship's officers were on board came back to save 12 people (Akarin included) out of the 1420 people (now are corpses) Afterward, the 3028 people in the boats had nothing to do but wait... wait to die... wait to live... wait for an absolution... that would never come.
Chinatsu, Yui, Warring Tsundres Himawari and Sakurako were also on Lifeboat#1 with Akarin and her later fiancee Kaito Mizuhara (a business and shipping magnate prodigy) and His mother were also on board while Akari's Sister (Akane) were waiting with Akari's Mother Asagi (now Seen but as a cosplay otaku like kyoko who eventually agree to the marriage of Kaito and Akarin foreshadowing an additional episode) at Tokyo Capital Jetty where the rescue ship brought them home after staying adrift for 2 days and later reunited.
One More Episode to wrap it all up now double length with the aforementioned characters from my previous comment killed off in the sinking in the previous episode and another Canonic crossover like the previous episode but with the 2008 *Mamma Mia movie canon which concides with Kaito and Akari-Chan's Marriage (who portrays Sophie and Sky) which became a double wedding (in stark contrast with the Mamma Mia story where Sophie and Sky postpone it to tour the world when this episode Akarin carries out the marriage as planned at the same time when Akarin's Mother remarries her long-lost husband)
Akarin's Mother (Who Portrays Donna) Finds her long lost Husband based on her memories on the climax of the episode (Who Portrays Sam Charmichael) who won the marriage with Akarin's mother in assistance with Akarin's 2 friends (Yui resembles Ali, and Chinatsu-Chan portrays Lisa) and they triumph. Meanwhile the other 2 possible fathers lost out (who portrays Bill Anderson and Harry Bright) when discovered that they are the fathers of Kyoko and Ayano who were now in their watery graves who took their own lives over the loss of their daughters.