In the most recent Kuro Fes interview where Fujimaki gave comments on certain characters, he states he purposefully writes Kise on the "losing end" of things and says he's an outlet of jealousy he has against Ikemen.
He has an even lower opinion on Haizaki (though few people can argue with that one). Fujimaki detests guys like him and wrote him (and Hanamiya) specifically to be detested by the fans, even stating that if Haizaki ever won the Kuro Fes popularity poll he would've dropped the whole fanbook project completely.
Yumi Kuroiwa, one of the animators, complained about working on the anime on her Twitter account. At one point, she even admitted that she lost Kuroko's character design sheet and decided to animate from memory. Along with posting explicit Yaoi fanart of Haikyuu!!, this was most likely what got her fired from Production I.G.
Fan Nickname: Ahomine for Aomine, to go with Kagami's in-universe nickname Bakagami. (Both aho and baka mean "stupid" in different dialects.) Also Kisecchi for Kise.
RIMFIRE is another one for Kagami due to the poorly placed song title in the season 2 opening.
Apparently, Murasakibara is becoming known as 'Titan' or the 'Purple-haired Titan' due to his huge stature; the scene where he's chasing after Izuki makes it seem like a scene from Attack on Titan.
Tsundere Carrot is one for Midorima due to his green hair and orange Shuutoku uniform
Fujimaki actually considered making Kuroko and Akashi siblings during the Teikou arc, which explains why they have similar hairstyles (their physical resemblance is something many fans had caught on pretty early). He shot down the idea because it might take the focus off the main plot and might "turn out like a soap opera".
In an early idea, Nijimura's hair was rainbow-colored. Fujimaki says he's rather glad he didn't follow it through.