a) I'm not nervous at all because Charles Manson would be back to jail again for violating his probation... I guess for a possession of machetes
b) such a tragic story but they most likely will not be required to be registered as sex offender. In case you didn't know, the Megan's Law varies among states and it's a case-by-case at judge's discretion.
BTW - a flaw in your B. Only one of them has to be a "minor" in order for other person to be charged as sex offender. It is legal for 2 minors to have sex with each other but it is illegal for an adult having sex with a minor.