I would absolutely shocked if there isn't a re-release of the Vaporfly 4% before Chicago marathon at the latest. New colorway, obviously.
So far we've had 5 colorways in 5 different drops between July 17th 2017 and April 11th (I think?) 2018. I would bet there is another coming soon.
As far as a new style, I know for a fact that a Vaporfly 4% with a Flyknit upper is launching in 2019 (in Europe at least). Burgundy colorway, 330 EURO retail. I believe the same sole unit.