Force and Destiny is the one you are missing? Or a splatbook? I have the three core books, but none of the additional ones.
I'm a Completionist. It's a very, very annoying trait, but once I have one book I have to have ALL THE THINGS! My bookshelves literally have dozens of RPG books that will never see actual gameplay (and probably have only been thumbed through once). With FFG Star Wars, I'm only missing Forged in Battle (I have all of Saga and D20 and the majority of WEG too).
Do either of you have any preferences for/about the game that I should know about? Do you mind if I go with a (modified) version of the introductory adventure?
It depends on which Introductory adventure you're using. I've GM'ed the EotE Beginners Box and the downloaded adventure expansion after that. The other two beginner boxes and adventures I own, but honestly don't remember a bit of.