I also saw a comment asking about Shikatani. Believe it or not I actually send some of my artwork with Shou-Chan and Shikatani along with other characters in the series before his story ended. Despite that, it seems the author ended Shikatani arc the way she believed that was a good ending to his story with him not replying back to his childhood friend despite all the stuff that happened between them. When Yuri and Jimmy arc ended with them being together in volume 7 she made a comment on pixie fan about Yuri Shikatani and Jimmy. She commented that she wanted to create characters who was a “pervert” but one of them had a love interest which was why Jimmy was created for Yuri which is probably why Shikatani doesn’t have one. Now of course she could change her mind however this was pretty recent so I kind of doubt that. Just a tidbit.
I for one am happy that the author is trying to finish this series as she started this in 2012 and we only got 7 volumes in 14 years. Though I understand people frustration and opinion is totally valid. But keep in mind this series is free (and still is after the publisher ask her to make it a book) that the author is putting out so im more less grateful to her that she doing that as there others series where things get drag on forever and takes years to finish. (In Japan many fans will happily wait for years for the author to finish this years from what i saw)
I will say this I do believe that Kashima and Toono is endgame. Author been hinting it for years and was pretty much confirmed by the drama cds and her statememt on Instagram years ago. Many fans confirmed this was true. And so far, it still seems to be going into that direction. It’s a but annoying (or slow pace) with Toono not coming down with his feelings and admitted it but he doesn't seem to be aware of it. Even on the author fanbox the author already said something is about to bloom in chapter 32, and after that fans were harassing the author about shipping wars to the point people were concerned about her and asking her to disable or do something about the comment section on twitter, pixiv.net or fanbox and even made a favorite couple poll in volume 7.
Yacchan and Toono is a cute duo. Won't deny it. Many fans can like what they like and it should be respected. For what I seen from the fans is to continue pushing for this couple as I still see many people (especially in japan) rooting for Yacchan and Toono to become Canon or make it proly. Even after what happened in chapter 32 people seem to want Yacchan to not give up or continue to fight for Toono which is what the author did though it doesnt seem to be heading in that direction. Even though it may not seem that way! She still gives them moments and things for fans to cheer on despite this. It seems that people dont want Yacchan to end up with Tamura which is why ppl are pushing Toono instead where Kashima has no one else to fall back on if Toono choose Yacchan. Also The author did say in volume three that things were gonna get more complicated when Yacchan fell in love so we finally seeing that. But now Toono is the one falling in love for first time and is struggling to come to terms with his feelings.
Other cast members either got their story arc cleared (which is why they dont have much panel time like Shikatani and Jimmy and Yuri right now) or they are slowly being revealed. The only arc we haven't seen much of is Akemi, Itome and Tamura which seen to be the only ones left.now. and now people want more Akizawa and Kon-chan and other characters to come in so we might get less of the club now but we shall see.
Kashima personally might have been changed after chapter 17 but again we also didnt know much about him to begin with but you could see that he had a secret already in volume 1 when Toono talked about the pudding and no body seem to know and continue to keep his dark thoughts hidden throughout the series. Even in volume 2 where Kashima could see Toono concern about their relationship, Kashima changed the subject as he didn’t want Toono to worry about it as he did in chapter 35. People complain that he was too prefect or to pure so now that something has happened in chapter 34 now its "out of character"? The boy can't win can he?