As Salamu Alikum,
A woman has all the rights to choose a good husband for her as long as he's a Muslim. However, she cannot choose a Kafir as a husband.
No one has the right to force a girl to marry anyone, but at the same time she does not have the right to get married without her guardian’s permission. The presence of the wali (guardian) is one of the conditions of marriage, and a woman’s marriage is not valid unless this condition is met. This is the correct view and is the view of the majority of scholars.(is this what you are asking?)
Yes it is allowed for a girl to refuse her parents choice.
the parents may like or dislike their daughter's choice, but as long as the person is good, the girl can marry.
Ya, the girl's will is superior to the will of parents, from the hadith: A woman named Khansa Bint Khidam once came to the Prophet and complained:
"My father has forced me to marry my cousin in order to raise his own status (in the eyes of the people)." The Prophet told her that she was free to dissolve this marriage and choose whomever she wished to marry. She replied, "I accept my father's choice, but my aim was to let the women know that fathers have no right to interfere in the marriage." (Ahmad, Nasa'i and Ibn Majah)
The guardian of the girl whether her father, brother or uncle plays an important role in her marriage such as finding a suitable match for her. But under no circumstance does this allow him to force his choice on her against her wishes. She is free to accept or reject his choice, or make her own choice.
check this out:
http://www.islamicfinder.org/articles/article.php?id=411
http://islamqa.info/en/22760
http://www.islamicity.com/dialogue/Q676.HTM