One theme could be the link between a person’s character and their hair. I would advise you to think about how Esperanza connects the different kinds of hair in her family to the different kinds of personalities in her family, including her own.
In the first paragraph, Esperanza describes her sister’s hair as “slippery.” That seems to align with her personality. One of Esperanza’s responsibilities is to keep an eye on her younger sister. She has to make sure she doesn’t wander off into trouble.
Another way in which hair connects to personality is with Esperanza herself. She says her own hair “never obeys barrettes or bands.” Esperanza’s rather rebellious hair seems to reflect her nonconformist personality. Later on, in the “Beautiful & Cruel” chapter, Esperanza declares that she “will not grow up tame” like some of the other girls in her neighborhood.
Another theme could be mothers—specifically Esperanza’s mother. You might want to note the fact that Esperanza’s mom gets an entire paragraph to herself. Meanwhile, her dad, her brothers and sisters, and herself are all put into one paragraph.
The special treatment seems to suggest that Esperanza has a particular love for her mother. You might have noticed that Esperanza favorably compares her to “the warm smell of bread.” Like bread, it’s almost as if Esperanza’s mom nourishes her or figuratively feeds her in a way that no other family member can.
As for tone, I think there’s two types of tones in the chapter. In the first paragraph, the tone seems more practical and efficient. The sentences are shorter. It’s like Esperanza has a checklist. She has to describe the hair of her dad, herself, and her brothers and sisters. She does so in a rather methodical, restrained tone.
In the second paragraph, the tone is less efficient and more melodious. The short sentences have been replaced with much longer ones. In my copy of the book, the first sentence goes on for more than seven lines. It seems like once Esperanza shifts to her mom, her tone shifts. It’s hard for her to be laconic about her mom. She loves her too much.