I would think its very likely they'll have a babes-in-arms session of New Moon. They usually have the popular ones and the girly ones, LOL!
We have only taken Phoebe once, when she was about your bub's age. We saw Harry Potter and even with all the loudness of the movie, she was quiet as a mouse!
Do you have a carrier? If so, can I suggest taking bubs in that instead of the stroller? I found if Phoebe started to stir I'd feel it and just bob up and down a bit. Worked a treat! I didn't even need to feed her, but I wish I had've though because after being so close to her for so many hours my boobs were going CRAZY.
And I would definitely go for an earlier session. Less people for you to worry about offending