I would like to reiterate that the person who both wrote and illustrated the Karami Zakari manga version is Kei Miike sensei. Everything including characters changed or adding a new character like Akaneya, the ending, etc are her idea. The only reason Airi Katsura (sensei) has been named as the co-author because she hold the Karami Zakari license.
What AK did to this manga is approve what KM sensei shew her before drawing the manga (KM sensei also drew it). KM sensei said she did it to be her own version. So, what you read is KM sensei's idea, not AK (sensei) who just approve it or ask for a little bit change (we don't know). I'm confident AK (sensei) got some idea from KM sensei to use in Grapara such as a strict mom who work as a teacher. (We don't know Iida's mom in doujin version do for living as she didn't appear)
That's why you can't predict Grapara's ending by Karami Zakari manga version at all. Again, Karami Zakari manga version is NOT AK (sensei)'s idea, she just says "Yes" to KM sensei's idea and let him/her did it. To be fair,
@diphuc1 , if you're not satisfied with the manga version, please blame KM sensei, not AK (sensei).
@jonasadan Iida in manga version stopped having sex with other guys since became the MC's girlfriend because KM sensei changed her to be just a normal girl with family problem background. But Iida in doujin is sicked,
nymophenia, she told the MC she's not satisfied with her boyfriend (in college) so she dated strangers on the Internet and had sex with them (cheating). Iida in doujin is AK (sensei)'s idea. So, the character reflects its creator, doesn't it? So sad.