You're both making heavy assumptions about what movie or food she will like. And that's my problem with the OP's date plan as well.
How much of this was planned because of conversations with her in which she has expressed interest in Brazilian food, or photography, or star-gazing? Or how much of it is planned because it "seems" romantic and what a woman wants?
The biggest mistakes are made by assuming. If you're unsure? Simple. ASK HER.
Not so much really. I like Steven Hawking. I think the guy is probably the smartest guy on the planet. I cannot for the life of me imagine being able to watch a movie featuring him and then feeling amorous at the end. The stargazing thing.. ok, sure. 2 hours of Steve explaining the nature of the universe? Ya.. sorry, no, not romantic.
I'm not saying that a Steven Hawking movie would make someone amorous. What I'm saying is that a chick flick might also not do the trick because maybe she's a woman who hates chick flicks. Plus, I'm not really fond of the idea that the whole purpose of the movie is to make the woman feel "amorous." It's a FIRST date. It should be about getting to know each other, not getting lucky.
(And just speaking personally, I'd be more likely to feel romantic towards someone if they appeal to my intellectual side, so yes, a documentary or Stephen Hawking movie just might work better than a chick flick for me. If someone showed me one of the gajillion Meg-Ryan-gets-the-guy film from the 90s, I'm more likely to be annoyed that he thinks I'm a stereotype instead of a real, actual person.)