The guys over at Brickset quietly updated their databases for minifigure series that will be coming out next year and it lists The Ninjago Movie Minifigure Series as one of them!
Just like the LEGO Batman Movie Minifigure Series, it is no surprise that they would want to launch a set of Minifigures along with the release of the movie.
No character list just yet but I’m sure the information will available to us closer to the release date of the movie which is 22nd of September 2017.
It also lists the Collectible Minifigure (CMF) Series 17 which was expected as there are usually 2 CMFs per year along with 2 ‘special’ series (ie. Disney, LEGO Batman).
There is no mention so far on the Disney Minifigure Series 2 yet but some of my sources have reported that they are in the works.