If you don't know how to use Game Maker 6.1 really well, you probably won't be able to get farther than the movement engine. Trust me. And working together programming can become burdensome when you are waiting for an update from the other member of your team. I prefer to work alone, it just seems easier to me. Having someone programming, and someone building the levels, and someone making the trainers, and someone writing scripts, and someone drawing sprites can become inefficient. Too many cooks spoil the broth.
It is good to make sure you can make a good test field, before you create a game.
Very true, and that is the easiest part of making a Pokemon game.
I hope you don't find my comments offensive, because they weren't meant to be.