The question of liability was determined by the Supreme Court of Canada ruling years ago; now it is just a case of the government paying for damages done.  This was an important ruling to protect Canadians from abuse by their government - which is what Chretien and Harper did through the positions and actions they took when Omar Khadr was in Guantanamo.  This is not about rewarding Omar Khadr, but compensating him for harms done by the government.  

As for Khadr's "conviction"; it is obvious to anyone who is not ideologically stupefied that Khadr's plea was the only way for him to get out of Gitmo.  It had nothing at all to do with his guilt or innocence.  And while I feel sorry for Christopher Speer's widow, her claim has nothing to do with this case, and will no doubt be summarily dismissed by a Canadian court.