In order to answer this question, you have to understand Squeaky, properly known as Hazel, as a character.  What is she like?  How does she behave?  What does she value in others?

Hazel is a strong and mature young lady.  She takes the role of big sister very seriously, and protects her brother Raymond, despite the fact that this action makes her alienated from her peers.  She is so loyal to Raymond that she is willing at all times to fight when he is threatened or teased.  She is also so loyal that is willing to let go of her own interest in running with thoughts of training him so he can have victory.

I’ve got a roomful of ribbons and medals and awards. But what has Raymond got to call his own?

Being protective of Raymond has made Hazel aggressive.  As said before, she is willing to fight to protect him.  Even when she isn't fighting, she stares everyone down with a cold and suspicious eye, almost waiting for them to start teasing Raymond.  This also alienates her.

In her interaction with Gretchen, we see what Hazel admires in others.  She sees Gretchen as an equal because 1) Gretchen doesn't back down from her stares and 2) Gretchen is more mature than the other girls, and doesn't partake in teasing Raymond.  Their equality is mirrored on the race track, and Hazel is content to lose if Gretchen is the one winning, because she respects Gretchen.

So, she is a loyal but aggressive person who respects strength and maturity in others.  Hazel would probably admire individuals who have overcome difficult lives and who are making a stand for what they believe in.  Oprah Winfrey might be one example, as would the following (you didn't indicate if they had to be living, so I included living and dead) - Colin Powell, Rosa Parks, Ghandi, Tom Hanks, Bono, Ellen Degeneres.