As White, can you play a Yugoslav-style attack in the Sicilian Najdorf?  (As I understand it, the Yugoslav attack just means you castle queenside and then pawnstorm the kingside, probably with a bishop along the a2-g8 diagonal)

Why is the Yugoslav attack typically mentioned against the Dragon but not typically against the Najdorf?

That setup is called the english attack and is used against the najdorf too. In the dragon the specific variation is called the yugoslav attack.

From what I gather, the English Attack may be specifically referring to the Najdorf, with people perhaps questionably using it to refer to other Sicilian variations with such an attack. The fact that there are lots of transpositions doesn't help. The Byrne attack is another name for it that I think is always referring to the attack in the Najdorf. In the Classical Sicilian it's often called the "Velimirovic Attack", but there are many transpositions. 

The Yugoslav attack is where you put a bishop on e3, then play Qd2 f3 g4 and h4. In the nardorf it is the same but called the English attack