Within your question, you offered many different titles (regarding literary texts). I opted to remove the titles from your question and identify their authors. Here are the titles:
Juan Ramon Jimenez: "I am not I"
Julio Noboa Polanco: "Identity"
"By any other name": from either William Shakespeare's Romeo and Juliet or Santha Rama Rau's short story "By Any Other Name."
Martin Earl's "What Do You Do?"
As for a thesis statement which ties all of these texts together (at least that is I am assuming what you are looking to do), it would be very hard to create. I would suggest that you include all of the texts you are looking to include in the essay in the introduction and make a sweeping statement regarding how literature (prose and poetry alike) speak to ideas regarding self-identity, self-definition, and the creation of one's character.
For example, here are a couple suggestions regarding a thesis statement which could be used to combine the above texts to the concept of making people who they are.
1). Within the vast world of literature, from classic and renowned authors such as William Shakespeare to lesser known modern writers such as Martin Earl, themes which illustrate self identity are both classic and essential in nature.
2. Given that self-identity and defining of one's character is universal, numerous different authors, of numerous different cultural backgrounds, attack the theme head on.