The look I was aiming for is captured better in the sketch on the left. I wanted the first shot to encapsulate a look of sadness and weariness, but with a small hint of defiance. The sketch on the right looks too defiant.
I then went into Flash to digitise the sketches. Wasn't over enamoured with either of the drawings and so I then scanned in the original sketch above and am going to try to draw over this in Illustrator to see if it is an improvement over the Flash drawings.
I will see how the Illustrator drawings look and then decide on what software to use to draw the characters in. I'm currently thinking of keeping the characters within the main scene black and white, with just one accent colour.