The rules make clear that I can place attachments with the "setup" keyword so long as I have valid targets for each such attachment. Obviously then I cannot place a chain attachment on setup unless I also setup a maester. But what if I place a non-maester character, an apprentice collar and another chain attachment? Is that legal because the chain can attach to the non-maester character once the apprentice collar attaches? Or no because at the moment all cards are flipped over, the chain would have no valid target?