1.) Kara is a Kryptonian! So she will likely smell different and have different BLOOD NOISES or whatever. Also her skin is impenetrable so you ain't ever gettin any of her weird alien blood. Use your best judgment for what all of this means. you probably know as much as i do about kryptonian physiology.

2.) she doesn't have any special hobbies! she does use a sunbed to keep her powers up but idk if that would impart any sort of smell.

3.) she ALSO has sharpened senses. maybe they will just know things about each other.

4.) no

5.) there's still time.