The info comes from some Russian Twitter site, so obviously take this with a grain of salt.
The info might hold some truth as Colin Farrell was said to be rumored for Constantine in the Justice League Dark movie at one time, but the JLD DCEU movie doesn't look to be happening as WB recently announced a Justice League Dark animated movie. Perhaps with the JLD movie not happening, it left Colin Farrell up for another role? Farrell also happens to be starring in WB's Fantastic Beasts and Where to Find Them.
Regarding Michiel Huisman, who plays Daario Naharis on Game of Thrones, it's possible he could have a Justice League role as the JL cinematographer happens to be Fabian Wagner, who is the DP for Game of Thrones. There was also that Justice League concept art of Game of Thrones actor Kristofer Hivju, so it sounds that at least WB might have their eye on some of the GOT actors.
Any guesses as to who they could be playing?
"Justice League" has a November 17, 2017 release directed by Zack Snyder starring Ben Affleck as Batman, Henry Cavill as Superman, Gal Gadot as Wonder Woman, Jason Momoa as Aquaman, Ezra Miller as The Flash, Ray Fisher as Cyborg, J.K. Simmons as Commissioner Gordon and Willem Dafoe in an unknown role.