Akashi: he’d smile at them a lot and even return their hugs, eventually telling them when he believed the time was right.
Aomine: he’d deny his feelings for the longest time, but wouldn’t want to tell them about it (he’d take joy in their affectionate actions, though).
Izuki: would win them through his superior punning skills that never ever fail to woo people. like ever.
Kise: he’d be very affectionate back, wanting to spend all his spare time with them and being upset when they weren’t around.
Kuroko: he’d tell them to calm down a bit, especially in public, but wouldn’t be too against it. If he realised he had feelings for them, he wouldn’t say much in fear of ruining their friendship.
Midorima: he wouldn’t be very good with dealing with affectionate acts, but he’d give them their lucky item for the day and suggest things that would bring their luck up.
Murasakibara: he’d share his sweets with them, but it would take him ages to actually realise that he liked them like that.
Takao: he’d give physical gestures like touching their shoulder or poking them affectionately to show he was interested.