Tiago is in the bizarre position that all my disparate characters want to be friends with him, bar Luke, and that's just because Luke is shy.
Valentina is happy to have another friend. She's pretty tolerant so isn't about to judge him for his habits, and she's familiar enough around him to have let her guard down, so... yeah. Friendsies.
Barney wants to talk to him about SPORT because he loves SPORT and this extends to muggle sports as well. He's a bit.... what? why?... about Tiago's habits, but, well, okay.
Mel is happy to have someone Portugese at the Model ICW and will certainly attempt to talk to him about Portugese politics, so that should amuse you, watching me flail around trying to work out what I'm talking about. She''s pro-legalisation but not interested in weed herself.
Lee wants to get high with him and talk about pretty girls and Quidditch :-D
Yakov likes his laidback attitude and will be friendly enough. He is open to getting stoned, but that would probably be a really bad idea because seriously, Yakov does not need to get any lazier.
Aaaaand Luke is timid and awkward ound the foreign people, but is generally pleased to have people around who know about muggle stuff so you never know, there might be conversations at some point.