I agree with Little Skylark, you should really gather some information before handing them pregenerated PCs. On the other hand, you could build about five or six PCs and then let them choose which one they prefer, but you'd end up wasting a lot of time on the ones that won't be used and might even skip the kind of class they want to play (when you talked about your players' interests I immediately thought about a bard or similar class with good roleplaying options).
Although I find the beginner box a great start, playing through an adventure YOU wrote will make them trust (and appreciate) your role as a GM way more than being just the "referee". My suggestion for a first time adventure is: 50% talking, 50% fighting; only two or three combat encounters (the first should be a warmup, while the others could include an interesting location, or a puzzle), and some interesting NPCs (not more than three, I'd say). As has already been said, just throw them into the setting with a brief introduction and make them talk to people: a skill check or two could be great to introduce them to the d20 concept... and then you can plan a little combat because well, kicking ass is always nice for a first timer. No need to explain difficult rules ahead of time!
(by the way, first post here. Happy to join the community, folks!)