Until I see a real, definitive announcement, this story will be just Fox and Viacom posturing to get attention, reining in salaries, etc. Years ago, there was a snit between Fox and the cast of The Simpsons with a casting call too. Obviously, it worked out because the six key voice actors remain.
We’ll know the reality soon though, San Diego Comic Con is soon and the Futurama gang is slated to be there.