They can have all of the rights that start with "You have the right to remain silent."
I wouldn't even give them that, I'd love to hear each and every one of them scream in agony for the week it would take to properly torture them to death.
It would be nice if some police officers who are experienced in hunting down perverts who find victims over the Internet were to publish some techniques on a website. Private groups of concerned citizens could pose as children, and lure the pervs into a trap. A weeklong torture session would have about an hour of highlights that could be posted, maybe make some pervs think twice about finding kids online.