What does the language in the description of Ralph foreshadow?

The first sentence of the novel describes Ralph as "the boy with fair hair." As a leader, Ralph will prove to be "fair." He has the best intentions and uses the conch to give everyone who wants a chance to speak the opportunity to do so. He is the "fair" leader whereas Jack will prove to be the tyrant. In the opening paragraphs, before he meets Piggy, Ralph continues to be named "the fair boy." 

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The first sentence of the novel describes Ralph as "the boy with fair hair." As a leader, Ralph will prove to be "fair." He has the best intentions and uses the conch to give everyone who wants a chance to speak the opportunity to do so. He is the "fair" leader whereas Jack will prove to be the tyrant. In the opening paragraphs, before he meets Piggy, Ralph continues to be named "the fair boy." 

Ralph has the appearance of being between childhood and adulthood. He has "lost the prominent tummy of childhood." He is in a maturing stage. He looks athletic but not in a threatening way: 

You could see now that he might make a boxer, as far as width and heaviness of shoulders went, but there was a mildness about his mouth and eyes that proclaimed no devil. 

This description suggests that Ralph is physically fit, having a look other boys might be intimidated by or would admire. This is confirmed when Piggy watches him in the pool. "Piggy appeared again, sat on the rocky ledge, and watched Ralph’s green and white body enviously." Given the "mildness" Ralph expresses, this shows he is, again, a "fair" and reasonable boy. Physically, Piggy is Ralph's opposite. Ralph is lean and moves with confidence. Piggy is fat and awkward. Ralph is a natural and fair leader in physicality and mindset. He is someone the boys would look up to for the way he looks and someone the boys will respect because he is a fair, mild leader.