I don't really like how the story evolves.
Even if Riri might be more bi than homo, and I understand that she could get friendly with Itta, Fuuka is very clearly not able to have a relationship with the opposite sex. This is made very clear several times. So I think, she wouldn't turn to another guy of all things to find consolation. I'm sure, if ever, she would seek out another girlfriend long before even considering a boy.
But then again, this would be another story. Although probably one I would like more.
I can't help but think that Haru is in fact Taichi's son. I have two clues to base my guess on. First, he really looks a lot like Taichi. Way more than like Tomo. This was my impression right from the start, when Shinobu saw him for the first time at the cafe. Secondly, the way Haru draws the Latin characters and how Taichi reacts in chapter 23, just short after Taichi told his feelings about the western script to Yoshimi when explaining why he decided to become an English teacher. I have the strong feeling, the mangaka wanted to give a hint here. What do you think?
Someone wrote about the age of Hana being 14, so I actually looked it up. In chapter 24 Hana's father asks Henrik how old he is and he answers with 22. Later in chapter 41 he reveals in a monologue he believes he is six years older than Hana. So assuming he is correct in both cases, this makes Hana to be 16. And this is also plausible since she finishes junior high school shortly afterwards and in Korea the students graduate junior high school at 15-16 years old (see https://en.wikipedia.org/wiki/Education_in_South_Korea#Middle_school).
I'm not saying it's completely appropriate for Henrik to have romantic feelings for Hana. But since he never really pushes her in this direction, decides from the beginning to reveal his feeling to her only once she finishes school and even withdraws after she chooses Aster, to call him a pedophile is a bit much.