Assuming that FFG wants almost a year between waves. Wave 5 will likely be this year. I'm willing to bet Episode VII merchandise will hit around November. So Episode VII will likely be Wave 7.

And of course, the question of how willing will JJ Abrams be in letting the designs outside to others well, well before the movie is out. FFG would probably need the designs by January 2015, at the latest in order to design a new wave.

WOTC is like the one company remaining on the planet that had Star Wars products fail, I doubt they'll be in the running to get bought up.

Speaking from experience though, I imagine Disney is happier to license then to be directly involved. If anything, they'd likely just embed some folks in FFG to work on products with them. Disney is smart enough to know that it is better to utilize a company that has contacts/experience/talent for a task, rather then try to start from scratch.