Thank you for this!

In addition to taking on those roles, I can recognize displacement of them at the same time, setting up 'actors' in the dialogue between the roles. It's hard to explain... using toys to express it as a child would be similar, but how that evolves into adulthood...

I wonder if it is useful to associate the three roles in that triangle with the enneagram 'centers':

Enneagram Gut Center - Perpetrator
Concerned with: Justice
Seeking: Autonomy
Underlying Issue: Anger

Enneagram Feeling Center - Rescuer
Concerned with: Image
Seeking: Attention
Underlying Issue: Shame

Enneagram Thinking Center - Victim
Concerned with: Strategies
Seeking: Security
Underlying Issue: Fear

Enneagram Centers of Intelligence - Enneagram Explained

The idea is that everyone has a 'core' identity in one of the centers, but incorporates all of them at one time or another.

That seems to fit well.