It really does seem like Flemyng slipped up. It was good wording from the interviewer. He asked the question as if it was common knowledge that Vaughn was confirmed. "Have you chatted to Matthew at all about any Star Wars potential..." And Flemyng seemed genuine in his giddy responses, until he realized he may have let the cat out of the bag.
I think Vaughn is all but confirmed for Episode VII, which I am more than happy with. First Class was quite well done (my complaints are with the script, not the direction). Layer Cake is a great movie and Kick-Ass was enjoyable at the very least. I think he will be much more of an actor's director than GL was, and I think he will be able to do the old (and new) characters justice.