[To that first question, Lord Zuko merely folds his arms behind his back and decides to remain elusive in regards to divulging anything else. Yes, he has a grandson, but the rest he ought to discover on his own. Having one's entire future mapped out, for better or for worse, can't be an easy thing to come to terms with.]

I'm not sure what else could explain it. The only time we've ever seen anything like this before is with the Avatar's capabilities to commune with the spirits of her or his past lives... I suppose meeting an older or younger version of oneself is almost similar.

[Which begs yet another question to ponder: if visions of the past are popping up all over Republic City, are they supposed to learn something from it?]