Constantine made an appearance on "Arrow", a lot of viewers loved that. Fan favorite Colton Haynes left the show in season 3. Mr. terrific is a new character on "Arrow" and fans like the idea of that. Jason Todd isn't in any show, but he might need some help. What could make the storyline.
The show would be called "Justice". With Roy Harper as Arsenal, Jason Todd as Robin and Constantine it could be very interesting, Mr. Terrific would be more of a computer man and weapon maker.
If any of it is true, i don't know, but it could be very interesting.
There are also rumors that Roy Harper is moving to "The Flash". Constantine joining Season 2 of "Legends of Tomorrow" with guest appearances in season 1, Mr Terrific is rumored to be the new inventor in "Arrow" for season 5. And nothing about Jason Todd in his own show or joining a CW Show.