So I guess to no one's surprise, Zeraora is the mythical Pokémon of this movie. To echo what others have said, I hope it has a more significant role (read: more screen time), and a more heroic role, than Marshadow did in M20. I also hope Lugia plays a more important role (read again: more screen time) in this movie than Ho-oh did in M20, even though the silver bird has gotten far more screen time in the franchise overall than its phoenix counterpart.
When it comes to the characters, I'm most interested in Ash (of course), Largo, and Lisa. The other characters sound interesting, but not as interesting as those three. In particular, I'm interested in Largo's connection to Zeraora.
Hopefully, Mayor Oliver is a man with good intentions who does what he believes is best for his people, and not a stereotypical politician who is only out to get reelected. Regardless, I wouldn't be surprised if, in trying to do what he feels is best for the city and for the festival, winds up inadvertently making a mess of things. And watch it be tied to his not listening to his daughter. You know, anime clichés and all that...