According to reports coming out of Redhill they are thinking of letting Copley go to another club, but still pay his wages, so unless I'm missing something here the Broncos still need to free up Salary cap cash and they won't do that by paying Copleys wages at another club.
By "pay his wages" I think they mean just a small proportion of it, enough to satisfy the cap.
Here is a list of Broncos current gains and losses for 2016 according to zero tackle. Bolded are the ones that are definitely top 25. Based on this, it's hard to see why the cap is even being questioned in the first place...
2016 Gains: Carlin Anderson (2016), Herman Ese'ese (Canterbury-Bankstown Bulldogs, 2016), Salesi Funaki (Wests Tigers, 2017), Darren Nicholls (Mid Season: South Sydney Rabbitohs, 2016),
James Roberts (Gold Coast Titans, 2017), Caleb Timu (2017)
2016 Losses:
Mitchell Dodds (Warrington Wolves), Jordan Drew (Cronulla Sharks), Mitch Garbutt (Leeds Rhinos), Jon Green (retired),
Justin Hodges (retired), Todd Lowrie (retired), Darren Nicholls (released), Jayden Nikorima (Sydney Roosters), Matt Parcell (Manly Sea Eagles), David Stagg (retired), Ashley Taylor (Gold Coast Titans),
Daniel Vidot (Salford Red Devils)
Also according to zero tackle
James Gavet is "off contract" but as far as I know he has been released so that is another top 25 loss.
http://www.nospam9/nrl/rugby-league/player-movements/