Do you think the fact that the hijacking worked on Peeta was a sign of any personal weakness or darkness? Do you think it would work on Gale or Katniss if they had been targeted in the same way?

I don't think it was a sign of weakness or personal darkness. It is designed to break down the strongest people. I think it would have worked on Katniss and Gale and it wouldn't be due to any weakness from them.

Peeta is a resilient character but he couldn't stop them changing his reality and rewiring his brain and perceptions. Everyone has anger in them but Peeta was not written as an especially angry character and there wasn't really any rage for them to manipulate in his right mind.