You failed to mention that, in 2010, the SCoC ruled that Khadr's rights remained in a state of "breach", and clearly made reference to Harper's refusal to offer "remedy".
As well, it was in 2008, after the first SCoC ruling that Harper demanded, by refusing to manage the Khadr file, that Khadr was given leave, by the court, against the arguments of Harper, that he could amend his request for compensation to 10M, from 100k.  
Then, after Harper still refused to act, in 2010, this compensation was again raised, against the arguments of Harper, to 20M, at the approval of the courts.
This means, until 2008, Harper could have settled this file for 100k.
And remember, he had already paid Arar 10M, in 2007, for a similar Charter breach, but refused to settle with Khadr, for 100k.
So, yes, Chretien was involved, as was Martin, but the bulk of this file has been in the hands of Harper, and it is he that has created the unwinnable scenario vis-a-vis Khadr's compensation request.