Tobias: flying or ghost
Ax: fighting or electric
Rachel: Fire or dark
Marco: Ice or psychic
Cassie: Grass or ground
Jake: Dragon
That's about what I first put, though it can be debatable. Tobias being flying is obvious. Ghost because he's generally looking on from a distance. The hidden eye in the sky, if you will. I also read a quote from Ax somewhere that if Tobias didn't want you to see him, then you simply didn't see him.
Ax I have fighting or electric. Electric because he's quite fast, and fighting because he's a trained fighter. Possibly better than Rachel.
Rachel would be fire or dark. Fire because she has an agrressive personality. Dark because she enjoys fighting more than the others. That's not to say she's bad. You can be dark without being bad or evil.
Marco is ice or psychic because sometimes he can be cold and ruthless. He can also be very smart and clever.
Cassie would be grass or ground, because she loves nature and is down to earth.
Jake would be dragon, because Dragons are generally revered in the pokemon games.
Like I said, the types could be debatable. There are multiple types that would fit each of them. This is kind of a weird thing to think about, though.
