I think we have it wrong talking about how Nico/Will and Magnus/Alex will react to each other. We're all so worried about Alex and Nico because they're both willing to kill and can kinda be unpredictable and it's like classic prep vs goth. And maybe they'll try to fight each other at first.
But. Soon they'll be fine because Alex will go "aw, this is just a goth baby gay. He's still figuring stuff out. I love him. I will take him under my wing"
And Nico will go "wow. She knows exactly who she is and isn't afraid to be herself no matter what... i wish i had that courage."
And they trade stories and both relate to each other on many levels. Like "oh, you fell in love with a straight guy? Yeah back when I was in middle school-" "your dad is considered evil, too?" "Yeah I also was raised in a pretty homophobic environment" "everyone is scared of me, too. I get it"
They'll become best of friends
Now Magnus and Will... we all expect them to be friendly and chill. Neither of them are super aggressive or competitive or big fighters.
However, they're too similar.
They'll take one look at each other and a primal instinct will unlock in the back of their heads, There can only be one.
It'll really be like "that guy is too nice, I don't trust him" "oh he thinks he's cool because he can heal people? Whatever" "well anyone who's anyone can glow, that's not a big deal" "i bet he's not even a natural blonde" "my jokes are funnier" "well my puns are cringier"
But they both pretend to get along because Alex and Nico like each other so much.