I'd just find it a little odd for Corni to showcase Pokemon other than just her Lucario here since it's the main hype tool that the writers love to promote. But even if she were to use other Pokemon, I'd rather see her use Kairiky or Kojondo: the former has had a lot of merchandise recently anyway, and she owns the pre-evolved forms of both Pokemon already.
I think the writers are just going to shoehorn in Galarian Pokemon where they can at this point. There's the possibility of (wild?) Morpeko being behind the food shortage at the park in that episode despite there being little reason for a Galarian Pokemon to be in Kanto. If that happens, I can't see why it won't happen with Korrina.