6. How does the archetype of the devoted comrade, exemplified by Damon and Pythias, affect the story?
Their friendship inspires change in Dionysus.
Damon agrees to stand in Pythias' place for execution if Pythias doesn't return from his homeland. Dionysus thinks Damon is silly to think Pythias will return, but he agrees. Just as the execution of Damon is about to occur, Pythias returns saying that his horse had died and he couldn't find another. He was so happy that he had arrived before Damon was executed in his place. When Dionysus sees the loyalty of the two friends, he decides to spare both of their lives.
7. How does the author create surprise in this myth?
The author sets up the expectation that Dionysius will execute Damon, but it does not happen
As stated above, Dionysus does not believe that Pythias will return from his homeland and will leave Damon to be executed in his place. We read the whole myth believing this is what will happen. The suprise comes when Pythias indeed does return for his execution, but when Dionysius spares both of their lives because he is inspired by their friendship and loyalty.
8. Which elements appear in the image, but not in the text?
The question is not complete and there is no image, so this cannot be answered as it is.