THE LATE BUT GREAT (this list, not him, he's very much alive) 707 / LUCIEL CHOI / [REDACTED] CHOI / [REDACTED] [REDACTED] HEADCANON LIST.
Can't be around alcohol or drugs. Cigarettes, even, are iffy -- but he's usually okay, unless it's the same brand his mom smoked. He isn't bothered - usually - by anyone else participating in these things, but he has sworn, sworn, sworn to himself to never use them, as he fears he's one step away from being like her.
Vanderwood, post-Rika death, was the first person to display care towards him. He'd injured himself, not even intensely, but enough to require assistance, and needed help getting in the bath. Vanderwood stayed, for whatever reason, and actually... washed his hair. Mumbled something about it looking nasty, so Vanderwood would take pleasure in doing it. That level of care toward him, even if minute, made him sob grossly. Like, he cried so much. Vanderwood got weirded out but still carried through with their task.
He takes great pride in his disguises / drag, it's not a joke to him -- though it does get laughs out of his friends. He has his own separate makeup for said disguises, and he's very knowledgeable in it. On occasion, specifically for his first viral cover, he's helped Zen with his.
The hair color and eye color we see with Seven isn't truly his.
His vision is so bad. Like, sooo bad. He 100% needs his glasses.
Naturally, his hair and eye color are dark, and his eyes are significantly darker than his brother's. Sometimes his roots grow out, but he takes great care of his Seven disguise, at least prior to his route's ending. Admittedly, his usage of color contacts being near-everyday and his job requiring near-constant technology use, his eyes are very strained, and are often hurting. He sleeps with them in, too, sometimes.
Seven has had countless identities and backgrounds for those identities. He has changed his body for them, he has changed where he lives for them. He has taken vocal classes for them. He holds no attachment to anyone whenever he is disguised, and often leaves their life without so much as a 'goodbye.'
Likewise, this means he's had many relationships, both platonic and otherwise. He's had sex before, in spite of his words, and isn't really shy to the idea of it. He will say he's never, himself, ever fallen for someone, or had sex that he felt mattered / meant anything in anyway, however.