[sanddrag]

I think one person should be officially designated as the team captain to stay on top of things but other than that I wouldn't have official positions. I would let people just fall into doing whatever they do best.

If found that a democracy style system where everyone gets a say and there are votes is very inefficient and nothing gets done. For a short 6 week timeframe, somewhat of a dictatorship is needed to get work done.

One suggestion I have:
Make sure everyone is not afraid to ask "why" of someone else's (especially mentors') proposals.

Also, a lot of the successful teams I've seen have very motivated adults pushing them. The adults can not take a passive stand on issues like event attendace or fundraising or meeting times, or strategy. Some things kids will not do if you just leave it to them.