Could it happen?

So it was recently stated that Cody, Bucks, Omega, and Page decided that they will all sign somewhere together. Let's take out personal feelings of where they will be best used creatively. That subject has been beaten into the ground. 

Let's just say WWE decides to sign them all in one swoop in January. Considering how radically WWE has changed their stance on working with other promotions in the last couple of years, does WWE actually allow Cody and crew to continue to do the annual "All In" event with ZERO involvement from WWE?
You're asking if Vince would knowingly let a competitor put on an opposing PPV just because they work for him?  No, the only point of signing those guys would be to try to ensure All In never happens again.