Mark Millar essentially confirms it:
“Fox have said that they want to build a cohesive universe and I’d personally like this to work in complement to the Marvel one. It would be cool if these universes didn’t contradict each other so if you went to see Spidey, The Avengers, the X-Men, etc, as a viewer you would have no idea that all three are coming from different studios. I’d love to make it look like they’re all just happening in one place.
“I don’t think it’s something anyone would want to rush into. Following that Marvel model, we want to establish things first. If you had a Fantastic Four relaunch, and Wolverine and the X-Men were in it, I think it would distract you from the Fantastic Four. You can make people aware that they’re existing in the same universe without making it a big crossover movie but it would be an injustice to the Fantastic Four not to make their first movie all about them.”