Does zimbardo make a deal with the devil in defending chip frederick, especially after what he implies later in the video about free will and heroism?

Yes, i believe so.
By defending Chip Frederick, i believe zimbardo has justify all the cruelty that he did when he's on that prison.
His defense that stated Frederick did what he did because of the system around him is unjustifiable because he practically gave order for other to do the cruelty even if he doesn't need to.

Ibelieve appendix i maybe wrong

United states v.  nixon, 418  u.s.  683 (1974),  was  a landmark  united states supreme court case  that resulted in a unanimous  decision  against president richard  nixon, ordering him to deliver tape recordings  and  other subpoenaed materials to a  federal  district  court.