Question: Does "the girl" - as she's been called - have a name? And is she a (or the) devil?
Question: Would the gas station still be called Shell and not the French word? Also, do they drive on the same side of car and street in France?
Answer: Shell is a Dutch petroleum company that may be better known in Europe than in America - its logo is the same worldwide. French cars have the steering wheel on the left, and you drive on the right in France.
Question: At the end of the movie, what was the light seen at the castle and where does it lead?
Answer: Lucifer was also known as the morning star. Depending on your view he passed the trial and was granted entrance through the ninth gate.
Question: How is it that Dean Corso is first on the scene of so many murders, but we never see him interacting with authorities? Corso is the first to find his murdered friend Bernie, he's the first to find the body of Fargas, and he's the first to find the Baroness strangled. Did he actually flee every murder scene without contacting the police (at least to clear his name)? Or did Roman Polanski deliberately omit police investigation scenes that might derail the plot with troublesome side-tangents?
Chosen answer: Corso is scared, both of possibly being blamed and of being the actual target.
Answer: She was not given a name, neither in the film nor credits. She is simply known as "The Girl". As to precisely who she is, it is deliberately left ambiguous. But the last engraving found by Corso does seem to indicate that she is the Whore of Babylon mentioned in the Book of Revelation.
Twotall