What literary terms are used in The Crucible and The Scarlet Letter to show Hester Prynn and John Proctor's suffering and the characters overcoming their sufferings?
So far I have symbolism (John Proctor not wanting to sign his name since it was important to him and Hester taking off the scarlet letter and the cap).
Symbolism would be an excellent place to start. To help you along, I would like you to encourage you to deepen your examination of the symbolism of the scarlet "A" that Hester Prynne is forced to wear, and in particular, the way that its symbolism changes during the course of the novel. Note how Hester manages to transcend this label as refering to something shameful and sinful and convert it into a label of admiration and honour by the end of the novel:
But there was a more real life for Hester Prynne here, in New England, than in that unknown region where Pearl had found a home. Here had been her sin; here, her sorrow; and here was yet to be her penitence. She had returned, therefore, and resumed,—of her own free will, for not the sternest magistrate of that iron period would have imposed it,—resumed the symbol of which we have related so dark a tale. Never afterwards did it quit her bosom. But... the scarlet letter ceased to be a stigma which attracted the world’s scorn and bitterness, and became a type of something to be sorrowed over, and looked upon with awe, and yet with reverence, too.
Note how this quote points towards the way in which Hester as a character transforms the meaning that is attached to the letter, making it refer to difficulties that have been endured and knowledge that has been won rather than it remaining associated with the stigma of sin and shame. In the same way, we can talk about the symbolism of John Proctor's "name" and how it is something that he will die to save and preserve.