@RimewindPhoenix we know from future glimps he married one of them. I really hope at some point, we will have an actual Yamabuki arc. So far we just jump from each girl arc but we have no Yamabuki arc.

@RimewindPhoenix my problem is..they are all great, but are their great for Yamabuki ? And I am not saying they are not on his level, but none of them contribute to his happiness - he is responsible for his own happiness and their happiness. I am not even sure you can call them friends with Yamabuki.

@Orion unlike in so many series that uses this gimmick, we can assume starting from chapter 10 that Apollo =/= final girl. Nisekoi had the stupid locker thing, Love Hina had the childhood promise thing. Here Apollo is actually..no longer important, as Yamabuki said - he had a chance to see who Apollo is very early in the manga and said "Nah, helping all those girls equally well is more important, no playing favourites" (I am paraphrasing obviously).

@Orion

. In Chapter 3 (“Liar”), Yamabuki explicitly compares Rikka to Apollo, and Rikka echoes Apollo’s on-air phrasing/apology about being off-key—an authorial nudge that she and Apollo share a voice and habits. 

Rikka is repeatedly tied to heartbeat and moon/celestial imagery (chapters “Celestial” #30). This tracks neatly with the “Apollo” (celestial) motif.  There were more hints and she even referenced Apollo during summer break. 

Apollo’s show restarts only after Yamabuki joins the broadcasting club—i.e., when Rikka gains proximity to him again. Of all the candidates, Rikka’s role best explains this trigger without requiring extra contrivances (she was the first to make contact with him for seemingly no reason after the school suddenly became co-ed and girls were not sure about interacting with guys). 

If Rikka turns out to be Apollo, she will simply have everyone say "oh yeah, that makes sense". The other one, which is a sideliner and not main, is Shinobu only on account we really don't know much

@Joel

while she didn't, I think she internally decided on it now. My hope is that it will show Nene as far more playful and friendly with Yamabuki now - to the point that will make other girls notice that the distance between them has shortened. She will still argue with him but it will be less aggressive. 

It was probably also important for her to be honest - I bet she was angry at him for changing the status quo - girls had fan clubs and people praising them and then this guy comes in and tells them they are inadequate and have to work harder. She hated him for that. Now she hates the distance she feels with other girls and she blames him again for it. She knows logically it makes no sense, but she can't shake this feeling. Voicing it, telling him that, was important to get over it. 

@2 yo kid I am a member of swarm myself. Neuro-sama is going to be our overlord soon and I just want to get into good graces early.

@Fable I would have agreed if she hasn't dumped him now and now is playing around with his feelings. I know she is a teen but felt like she was mature enough to admit when she wants something and what she wants