Just saw it. I'll post my answer here instead, so everyone can see it:

The exact types and moves of your pokémon don't matter all that much. Fights will be handled narratively, and we'll simply assume that type advantages play a part in fights regardless. The point of this game is the adventure itself, and the only thing that's important about the battles is that they're interesting to read. Thanks for bringing it up, though - it's always good to have as much clarification done as possible before the game.