At one time it was said there was Charlie Hunnam Flash concept art created by WB, though it never hit the net.
Obviously if that rumor was true, WB chose to go in a total different direction with Ezra Miller.
Hunnam also happens to be a fan-favorite pick to play Green Arrow in the DCCU (well, second fan-favorite pick, anyway).
Check out fan art below of Charlie Hunnam as Green Arrow created by Bosslogic, who is also responsible for some of the cool Tyrese Gibson as Green Lantern art.
To date, there has been no confirmation of Green Arrow appearing in Batman Vs. Superman or any other of the DC films, but the character was paramount in The Dark Knight Returns comic story that inspired the movie.