If Sabrina's returning I honestly want it to be a double battle. Between Gengar/Alakazam vs Gengar/Pikachu. On the topic of Dracovish, It's got a good moveset so far, Fishious Rend, Ice Fang, (Excluding Water Gun for now), because this Pokemon has been set up more on the Physical side. Dragon Rush or Outrage makes a lot of sense here, the last move I would want want to see would be Scald. Put the opposition with a burn effect. Work from there.
Reason for the double battle is honestly quite simple. With all of the returning people, get an obscure reference to Haunter and as Ash owns Gengar. Gengar vs Gengar, while Alakazam battles Pikachu. (Think of Riolu and Pikachu vs Chairman Rose's Copperajah and Ferrothorn). Since the Dragonite vs Dragonite battle showcased the same Pokemon can easily battle one another on screen.