Unbound delegates can vote for the candidate they choose if they are fully unbound. Some have bound themselves to whichever candidate wins their district, but my understanding is that unbound delegates are free.
Not according to this post, and many others. He’s saying they can change the rules at the convention and the pledged delegates can vote for anybody they want.
http://www.freerepublic.com/focus/news/3434248/posts?page=55#55