Honestly, I don't see Dawn as the battling type but what she participates in now, Contests. It is just a fitting stage for her personality in the anime and works well with her more than a battler would. If she was portrayed as one who wanted to enter the Pokémon League, then it would be quite an interesting change in view, however I see her more into Coordinating than battling Gyms and such. They tried to do this once with Dawn vs. Maylene in the anime, and as great as the battle turned out, Dawn still ended up sicking with her contest-like strategies to pull off a good fight.
As for her Mamoswine, more than likely Charizard would win that battle. It is stronger as it has more experience and like said, has been in training ever since Ash left it in Charific Valley. Not to forget, Charizard has a typing advantage as well. However, the thought of this and seeing how similar Mamoswine's obedience problems relates to that of Charizard makes me wonder. Will Mamoswine eventually leave Dawn as well to go off into training or protecting a group of Pokémon too? I would hope not because Mamoswine is the one Pokémon that actually gives Dawn a different look other than having "only cute" Pokémon for her team.
As for her Mamoswine, more than likely Charizard would win that battle. It is stronger as it has more experience and like said, has been in training ever since Ash left it in Charific Valley. Not to forget, Charizard has a typing advantage as well. However, the thought of this and seeing how similar Mamoswine's obedience problems relates to that of Charizard makes me wonder. Will Mamoswine eventually leave Dawn as well to go off into training or protecting a group of Pokémon too? I would hope not because Mamoswine is the one Pokémon that actually gives Dawn a different look other than having "only cute" Pokémon for her team.