I think essential would be the best word to use here, critical means necessary, but necessary doesn't seem like a word as strong as essential. In a good speech, it is essential to make all your important points.
Try reading out loud in the future, just to see how it sounds. It could be easier! :)
The third one is your answer
Poe, or more accurately the speaker, is posing that the bird is clumsy.
Because women at that time could not vote, which was also a disadvantage black people had. They could not vote either because they were black.
Answer:
Juan Thomas means when he says "the structure" is that the poor people are cheated from birth, but they made it through it. He is scared for Kino. It is important to the story because it foreshadows the things that happen to Kino.
