Eraviel "Childhood Friend (Who I still couldn't remember the name despite reading this for hours) seriously have issues. She's blatantly showing herself that she likes Jirou (And Mei even believes that. Surprisingly, I remember the side character's name well.), but then she hangs out with another guy happily? Dunno if that's an act or being forced (Though she definitely wouldn't make a face like that if it's forced) but I'm going to assume that it isn't."
I think Shiori views Minami as a friend. Shiori also seems to be overly introvert when it comes to intimacy. Jirou was her first kiss and usually hot chicks by the time they have hit 18 has had several boyfriends when it seems she hasn't, plus her and Minami stayed together when they had the option to choose another pairing, Shiori has implied she's waiting for her opportunity for Jirou but Minami seems gay to me, lot of the girls fawn on him, and Akari has failed many times to get his attention, which seems odd to me.
"Secondly, what the hell is wrong with Akari's character? It was already heavily implied (and even came out of herself) that she indeed is in love with Jirou, so I don't understand the point of her conflicting herself about her feelings with Tenjin. The chapter tried to be so subtle on it also by making Akari relieved that Tenjin wasn't in the festival which didn't serve any purpose at all when I've been slapped with the truth that Akari's not into him already."
The reason why she's conflicted is the times she threw herself at Jirou it always ended with him rebuffing her, and reminding her that "you have Tenjin, and I want Shiori" type of response (rejection is usually hard to overcome, especially when you lack experience handling it). The problem is two fold for her, she's teased Jirou enough that while he knows she likes him as a friend he thinks she's just teasing him (and not serious about him), and when she seems to breakdown it's usually because she failed after trying for Minami (guess Jirou is too good for pity sex). Jirou like most manga MCs is dense, unless he hears from Akari words along the line of "F Tenjin, I want you instead" he won't figure it out.
I do have to agree with Mei, for Shiori why does she like Jirou and that if she's not aggressive she won't get him. Let's face it, Akari has worn Jirou quite a bit, he does have feelings for her but it's misplaced because he thinks she prefers Tenjin over him, and he likes her enough to help her get Tenjin because he feels he can't have her. I think Akari will end up with Jirou just because she is aggressive and when one of her gyaru friends decides to clue Jirou in he'll realize he has another option, the best girl kind.