Is there any way to get the Dunsparce before Morty? If there is, you could do the old AI-exploiting trick where you repeatedly switch between two Pokémon, one of which is a Normal-type and get him to run out of PP with "but it failed!" moves. (It's how I beat him in the original Silver, and apparently it works in HGSS too.)So all six mambers are in,
Female dunsparce named Sarah. Teach it 2 HMs.
Seel, It must know Encore and Disable, and no attacking moves (Hail is permissible, Sheer Cold is not). It may evolve into Dewgong after causing any gym leader's pokemon to faint due solely to Struggle recoil. Nickname it Pacific.
I will evolve that seel!
Dunsparce can be caught in Violet side of Dark Cave. They are rare there (~1%) unless they are swarming. That means you can get one before you reach Violet City.