Hello, bit of a bump. I forgot about this due to RL issues, sorry about that.
I have some ideas that might help
A) There should be a manager role, who is responsible for communication between the members, setting deadlines, etc.
B) Design and Coding elements should be seperated. Coming up with fun game mechanics and interesting levels is better suited for the Creative's jobs. Design role should become the Programmer role (comming up with pseudocode/techdemo's of systems in action, in particular demonstrating clean and efficient solutions).
C) Either the challenge should be broader (designing a game, rather than just a character) to justify the 6+ members, or the teams should be smaller (as having 3 artists and 2 designers working on one character is a bit difficult due to too much overlapping skillsets)
1) Broader challenges should have in the team:
a) exactly one Manager
b) exactly one Designer
c) any number from the other roles, but at least one from each. For example, two artists could each draw a protagonist and an enemy seperately.
2) Smaller teams (doing the smaller challenges) should have
a) exactly one manager
b) exactly one designer
c) exactly one artist
d) exactly one programmer
D) There needs to be some official channel of communiation, e.g. this thread, or some IRC chat, that the team uses.
A general approach to doing a challenge could consist of (managers make sure that whatever chosen plan is followed):
1) Creatives comming up with a basic theme and genre.
2) Creatives write down some keypoints for artists (style, necessary assets ("Plumber Protagonist sprite", "sprite for an evil turtle that trows hammers", "throwing animation for evil turtle" etc)), enough to let the artists commence work.
3) Creatives come up with some specifics on game mechanics. Given the short ammount of time, the design should focus on some novelty, e.g. player presses spacebar to a rythem to shoot laser beams, or something. 2 and 3 happen in parralel, and with input from the artists (what they can and can't draw) and programmers (what they can and can't program).
4) Artists and programmers do their thing. Programmers need to be sure to inform artists of any technical limitations (POT textures, alpha channels etc).
5) Creatives work more on the backstory and refinement (ideally not so much as to render previous work done in 2 and 3 obsolete).
6) Manager collects assets and assembles them into some presentable format (doesn't have to be elaborate, just a forum post would be enough).