¿Cómo estás? means how are you?
and well I have to say that ¿Cómo son tu...? does not exist.
You could say ¿Cómo es tu...? that means How is your...?
and also you could say ¿Cómo son tus...? that means How are your...?
¿Cómo es tu casa? <> How is your home? (Hmmm... for example: Mi home is big, or red, or something like this).
¿Cómo son tus libros? <> How are your books? (Example: My books are great)