I think communal bbq is a great idea, that way people will mingle better rather than splitting off in to little groups, plus I can't cook so I'd starve. (of course, if I BBQ, you'll all have to make sure you've had your jabs!).
disposables for definate.
Price per head is a great idea too.
I could sing for everyone, but I offend myself in the shower so potentially we could require an ambulance.