(I’m going to assume they’re a little aged up for this. Also, caveat: I have never personally been drunk, so I don’t have a lot of frame-of-reference here.)
Green gets really emotional. Once while drunk, he tried to hug all four of the others at the same time, saying “I love all you guys” with tears in his eyes. If he continues drinking past that point, he probably passes out and starts snoring really quick.
Blue tries to tell jokes, but they make less and less sense the more he drinks. When he’s really drunk, he ends up at the surrealist sort of “Why did the cucco cross the road? Fourteen!” level of lolrandom humor.
Red holds his alcohol better than you’d expect – or maybe it’s just that he doesn’t have many inhibitions in the first place. He’s maybe a little more cuddly than usual? Really hard to tell, considering the baseline is already so high.
Vio doesn’t drink, because he hates feeling like he’s not in complete control of himself. (He was faking it at the Fire Temple.)
A drunk Shadow is a Shadow who has lost all ability to discern good ideas from bad ideas. Dare him to do something. Just about anything. He will do it. He’ll probably shout “parkour!” first, too. The fact that he actually can do parkour is worth nothing, either: he’s gonna fall flat on his face.