1. Speedy is in the hospital. He's in police custody, though.
2. The Very Old Man is an insider with the people who owned the boxes (the organization). His original plan was to steal the boxes and blackmail them into giving him something he wants but this did not work (the organization that The Machine refers to as The Usurpers are apparently tough negotiators) and Thin Tommy started giving him trouble, so he decided to take the boxes for himself instead. His other plan was to simply blackmail them until they capitulated, then give up the location of the boxes.
The Very Old Man actually set up the whole job and is the reason that Thin Tommy suggested the location he did - he has inside access/knowledge regarding the organizations members and their kids, and as one of their security experts, he knew where they would be and that they would be mostly unprotected.
He initially wanted the hostages as an additional source of leverage. When he figured out that they weren't going to capitulate he didn't care about the hostages anymore, and just wanted the boxes to see if he could figure out any way from the boxes to extend his life or cure his illness.
Essentially he always thought he had advanced far enough in the organization to be entitled to special treatment and when he was declined he decided to turn on them.
3. Fred the Caretaker was a black book operative in the Vietnam war. After the war, he was hired by Card's grandfather as an assassin. This was his "retirement reward" a position being basically a groundskeeper. He was pretty old, in his late 70s, so you can imagine what he must have been like when he was younger. He was utterly loyal to Card's family and to a lesser extent to all the organization kids.
He was in addition to being an excellent killer, a trained "psy ops" expert who had a lot of training in creating terror and demoralizing an enemy population.