Well there's a Dragonite being used and that's no one's ace in the anime. There's also a Rillaboom on the field (probably Leons) and that's not an ace eitherThe preview is likely all from that first "The Curtain rises" episode. It's an opening ceremony showing all the champions test their Pokémon out. The scoreboard screens are blank.
That's also why we're only seeing each character use their ace.