Juri wants her daughter [Yuuki] a normal life and Juri wants to hide her from Rido, Juri's brother, who wants to take Yuuki's life...
Yuki Cross's theme song from Vampire Knight is just called "Yuki Cross's theme". It's the third song down listed in Vampire Knight: Original Soundtrack.
no
Ummm she was born that way but her mother Juri or something like that sacrificed her so Yuuki's vampire genes were suppressed, temporarily tranforming her into a human.
No, Yuki and Kaname are not biological siblings in "Vampire Knight." They were raised together as siblings at the Cross Academy, with Yuki being a human-turned-vampire and Kaname being a pureblood vampire. Their relationship is more complex and intertwines romantic feelings and past connections.
vampire knight episode 7
Cross Yuki's eyes in Vampire Knight are depicted as a reddish-violet color. This unique eye color is a significant characteristic of her vampire lineage.
Zero Kiryuu
In the manga but not in the anime.
Yuki Kuran fancys her fiancee/husband Kaname Kuran.
no
Kaname Kuran is a handsome, intelligent true-blooded vampire who is Yuki Cross's ancestor, but Kaname transformed himself to a baby and was raised by Haruka and Juri as Yuki's big brother. Although in my opinion, Zero is way better than Kaname...
Yuki has a flashback about Zero joining their family in the second episode of Vampire Knight. In that episode, Yuki remembers how Zero was taken in by her father and brought to live with them after losing his family to a vampire attack.