I'd say Si ego. Her expressions and her way of talk are really slow even if she enjoys projecting otherwise on scene. Another choice would be EII, she reminds me of Kristen Stewart who I think is EII. Obviously the look of Gwen is drastically different, but their way of talk and move is similar.
She looks somehow unemotional to me. Kind of cold, lazy, sluggish behind all her make up.
The difference on the image she projects on pictures, videos and stage and her real self is evident in this one with scenes from the shooting. She knows how to stand, how to pose, how to smile, how to sell. Actually I think she hides a lot of her unemotional and introverted being with the big static smile.
Her lyrics aren't really 4ish even if she wants to stand out with her look, I'd say 3w4 and 9 on tritype.
I've heard that she's really smart, like she knows what to do on Hollywood and what image project to the public to sell and she's extremely polite socially.