me gustan los chicos
¿Te gustan los chicos blancos
You say, "gemelos."
You can say los chicos for the boys, and las chicas for the girls.
hola chicos
Nothing, that's in English. But if you meant to say HOW to say teenage boys, then its "adolescentes"
Odio los chicos.
acelerado for boys and acelerada for girls
Nuestros muchachos. (Chicos, niños.)
girls, debriefia and boys, debriefio
Girl who are friends are amigas in spanish. Further boys are amigos
You could say "los niños son jóvenes".
Los muchachos tienen problemas