が and は in the same sentence

[thesuker]

Would this sentence be correct?

私が友人は変態で は ありません (Of all my friends, I'm the one who isn't a pervert)

 

[Mike Cash]

Would this sentence be correct?

私が友人は変態で は ありません (Of all my friends, I'm the one who isn't a pervert)

No.

友人の中では変態ではないのは私だけです。

友人の中では私だけが変態ではありません。

The first is closer to your English sentence. The second is closer to the Japanese construction you're targeting.