"I hope their parents have the means and the desire to sue until the cows come home to clear their names and let them get on with their lives."
In order to prevail in a malicious prosecution claim, at least in most jurisdictions, you need to have prevailed in the criminal case (been acquitted or charges dismissed). One of the reasons the the prosecutor may be clinging to this case is that, if he drops it, he will be making it easier for his office to be sued. I can't think of any other reason to continue with this dog of a case.