Why does Sophocles include this argument? to show that only the gods are capable of mercy, which is why Creon and Antigone are given opportunities to avoid their downfalls

to show that Antigone acted mercifully in giving her brother a burial, but Creon's lack of mercy leads to his and Antigone's downfall

to show that both Creon and Antigone acted mercifully, but Creon's excessive mercy is the source of his downfall

to show that neither Antigone nor Creon is capable of acting mercifully, which leads to both of their downfalls

peace, morning, sun glooming, sorrow, woe pardon’d, punished, more hence, talk, story. all of these three words have to do something with a depressed, regretful tone. woe is another word for misery, heartache, so all of these words are about unhappy feelings.

yes this is an analog in my view

specific audience will understand the main ideas. for example, if you were writing an instruction manual for rocket scientists, it would likely look very different from one you would write for young children. your language, tone, and writing style would change significantly.