In what circumstances would your character drink alcohol: If it was required for the mission at hand, Hei would consider it, but Huang would have to demand it. If left to his own devices and only in extreme circumstances, he might spike his own drink. Just a little. Or his food. Sake and wine add such a unique flavor...
How much would they normally consume? Very little. Alcohol dulls the senses and Hei would never ever let himself go like that. Not when he's already made the biggest mistake he can imagine by letting his guard drop just the once.
What is their alcohol tolerance? Decent to middling good. The question is, though, how much is he actually drinking, and how much did he feed to the poor plant sitting next to him?
What kind of drunk is your character/how would they act if they were drunk? Paranoid, grouchy, bite-your-hand-off (figuratively) if you get to close and generally just the silent drunk type. On a good night, you might get a maudlin Hei. He does miss his sister something fierce... and there's all that pent up guilt over her disappearance too.
Who would they go drinking with if they had to choose drinking buddies? DtB universe: Nov. 11, assuming either one could refrain themselves from killing each other right away. Misaki, maybe, but he's really only being polite and going along with her. Marina? Faith! They practically already planned it once, albeit with him behind the counter but that can be just as fun, right?
What's their alcohol preference? Beer, wine, mixed drinks with fancy names? Sake if it's with a meal, otherwise any hard alcohol is fair game with a slight preference for scotch on the rocks WTF self? Where'd that come from.
Green alcohol y/n? He'll serve the green beer with a smile and maybe a leprechaun's hat if the job required it, but he's not touching it otherwise.
Your character is completely drunk. Who do they drunk-dial, and what do they say? Mao, because he figures Mao will talk some sense into him and if not, at least his fur is soft for the sleeping on. Never ever Haung. He'd never hear the end of it.
Marina: However much fun it'd be to call Faith, he'd probably call Conrad first. Less teasing prospects and he's already set up a little bit of CR so it'd be in character for "Li" to do so. Plus, he isntinctively trusts Conrad to keep things to himself so if something was slipped, at least it'd stay hidden while Hei tried to do damage control. Of course, there's always the prospect Conrad will put two and two together...