I think post-game Lucina x Owain might have (it says they may have but nobody is sure), but otherwise the rest of the children characters seemed to have stayed in the past. They are releasing a DLC soon where they allow you to see the doomed timeline, though.
really?! that's great cuz I was rushing and trying to get all their support convos ;v; eheh.. also yeah i heard about those eheh ^Q^ that would be so cool omg would you have to pay for it though? arghh