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.

Complementary goods. they go together, thats why one price increase and the others demand increases