his favorite hobby is
"Qué es su favorito" means "What is his favorite one?", so the answer would situation-dependent. If you were talking about ice cream, you could answer "chocolate" or "vanilla". If you were talking about animals, you could answer "perros" or "gatos", etc.
"My favorite color is green" in Spanish is, "Mi color favorito es verde." It is pronounced, "Me ko-LORE fah-bo-REE-toe es VARE-day." Sites such as learn-spanish.co.il provide audio pronunciations of many common Spanish words.
el azul
blanco marino negro y rojo
... es su (usted, ustedes) / tu / vuestro cantante predilecto / favorito.
Fanny Lu ha mencionado en diversas entrevistas que su color favorito es el rosa.
¿Cuál es tu/su día más favorito de la semana?
No estoy seguro que' animal es su favorito, pero ella tiene 5 perros de rescate, así que ella le gustan los perros.
Cuál es su nacionalidad = What is your nationality.
¿Cuál es su / tu / vuestro restaurante favorito? ¿Qué lugar le / les / te / os gusta más?
If you are trying to say my favorite season is... Then you would say Mi estacion favorita es...
"Juan es su nombre" means "Juan is his name" in Spanish.