I agree with litteacher. Since your teacher wants you to focus on the endings of the poems, I think it is important that your thesis touches on what each ending is trying to accomplish. It is good that you recognize the way the first poem answers the question at the end, but what is the other's ending trying to do? Is it different? If is it not very different in construction, is it thematically different? This might help in coming up with a different you can highlight in your thesis. I like the complexity you have so far, now look for what the poets were trying to do with the endings.