There isn't a "canon Warrior of Light", or rather, your character is the canon Warrior of Light for your playthrough. All starting cities are equally valid. My understanding is that the Midlander in the cinematic (called the Meteor Survivor or "Derplander" by fans) is a stand-in for your own character. It's interesting to explore what Meteor's canon backstory would be like, though.

That the Halloween event lets you transform into him is a bit of fanservice for players (to let you act out scenes with other NPCs). (Last year, a few people showed up in Meteor's 1.0 archer outfit...)