First off, blue hair was not a defining characteristic of the Zealians. Secondly, wouldn't Serge being the descendent of Magus be technically a form of incest when he marries Kid? I mean, sure, they are far removed after 400 years, but it he would literally be hooking up with his great, great, great, great aunt. That's a little too weird for Square in my opinion.
TOO WEIRD FOR SQUARE!? DON'T EVER SAY THAT! WHEN YOU DO A GREAT SERIES LOOSES ITS QUALITY! I remember the first time that was said about Square the result, FF:MQ. You may have just got us Chrono Brake, but it will now be full of plot holes and spelling errors!
But I'm going to say that I highly doubt that Serge is Magus or even his decedent. It would be more likely that Schala sent him home with Crono, Marle, and Lucca.(even if there is the possibility of not having them in your party, it's cannon not game mechanics) It's just much more likely to me that Guile is Magus and this is the way Kato wanted to explain it. Now I'm not saying your theory is wrong, but I feel it is very improbable. The Guile one is improbable, but more likely and it is opinion none the less. The reason why I say Magus was sent with Crono, Marle, and Lucca is because there were two Magusseses...s[(Magi?)... That is annoying we need a separate name like Magus B] and she sent them all to the same timeline but since one of them wasn't from that timeline she just threw him there, landing him somewhere before 1020 or even at 1020. That's my theory, but your theory has some better support to it.
