This post has turned into is "Kid" a proper name or not, which is alittle odd.
Here are my beliefs
1) Magus is not Serge, Although I doubt Schala left her brother alone, she may have found him without it being shown.
1a) In a more depressing light you could say that Magus is not Janus in Schala's eyes. Magus has done horrible things in a quest to take vengence. A Concept that Schala would not aprrove of (She helped create a monster that could not be killed with violence! Damn if she wouldn't be willing to abanndon a guy who can kill without remorse!) so Schala may no longer see "Magus" as her brother and is waiting for him to redeem and find her. (See below*) Waitn for him to become "Janus" again (sure he's not an all around plesent kid, but not evil or willing to murder either)
2) The photo could be another world and thus the point of who it is is moot. The face is blocked out in game so you can imagine who it is. If you wanna say it's serge then it's serge....I woudl liek to point out that in the interview he wanted us to think about our world....what I am suggesting is
It's you...or me...or whoever. That girl is our worlds (or another worlds) Kid with her worlds Serge or whoever. I perfer to think of it that way because I mean Serge leaving Leena is cruel and I can't imagine doing it. Thus in my game he didn't. Perhaps that's the point, to put yourself in Serge's place. In that world afetr everything that happend how would you have wanted things to go?
Will Serge leave Leena for Kid? Is that the same Serge? Is that even Serge? What happened to everyone who was with you?
I think the point of the ending was missed by us. It doesn't matter if Serge was Magus (which makes no sense) or something like that.
What matters is that Ideal Timeline is what we think it would be. Who was better off? Who did Serge love? Its not supposed to have a single answer, it's supposed to be what we think it is. Do we think that there is a Kid in our world, are we that Serge she is looking for? Is it supposed to be love or just a deep friendship? It's up to us to decide, not something that has been predecided. Throughtout the entire game you are pulled around and manipulated, I think there was a reason for that, a reason why the storyline was so confusing. I'm not sure you understand what I mean but anyway...
I know we are a Compenduim so we serch for answer, buu in this case maybe there is no single answer as to how everything turned out.
3) The dresses look fits thet style of the clothes worn in El Nido no the clothes worn on the mainland. Why are we even comparing the styles anyway?
*In Lucca's Letter she calls him Janus. Is it possible that he is actully attempting to redeem? When I say find Schala I mean her who she was. In his current state he has no right to face her. (Think about the DS versions ending) You could say "she doesn't have a rigth to be all high and mighty after almost eraseing existence" but that would ignore the fact taht she was not quite all there when she did it, well Magus was 100% aware of himself when he decided to be an evil basterd.