So the only one left alone is Shino, and the other 3 are like in a love triangle... Chihiro and Nao love Aoi, but who does Aoi love? (poor shino XD)
Aoi is somewhere is a grey area. She likes or thinks she likes Chihiro, but it appears her feelings are slowly moving towards Nao as noted when she, Aoi, questions the feeling in her chest (http://dynasty-scans.com/chapters/chouchou_nannan_ch03#20).
As to Shino, I still think she and Chihiro will end up together. Unfortunately, I'd liken Shino to that of the consolation prize.
OK, so if Chihiro is yandere, how would this play out? Would she 1.) start doing little things to keep Aoi and Nao from getting closer? or 2.) do little things that keep Aoi off-balance such that Aoi continues to think she is in "like" with Chihiro? A yes to the first option supports the yandere hypothosis and implies that something bad could happen in upcoming chapters. A yes to the second option does not dismiss a yandere hypothosis, but could imply Chihiro is the jealous type and may want to keep her harem of admirers intact, so Nao "better not 'f' with her shit." I don't completely buy option #2, as that might cause Chihiro to alienate Shino. and if Chihiro were the type to want a bevy of admirers, then alienating Shino would be the last thing she would want to happen.
Now, let me offer this small monkey wrench into the whole love polygon thingie: Chihiro likes Aoi, and is the yandere type. Aoi likes Chihiro, but is slowly being wooed away by Nao's kisses. Nao likes Aoi. Finally, Shino actually likes Nao, but is mre the dandere type and has not made any effort to show it. Oy, how would that work out? (umm, OK,I'm not sure I completely believe this statement myself. I'm just throwing it out into the realm of possibilities)
And please forgive me, I guess I'm rambling because it's past my bedtime. so on that note, g'nite all.