You don't really need the business license until you made 5000$ of income thanks to the products you made with C2.
But each member of your development group needs to own his own license (if C2 is used on different computers).
If different people use C2 but on the same computer, you might have a business license setted to the name of the company/group (not only of one user).
If you're unsure mail licensehelpjyw@scirra.com and give a precise description of the structure and way C2 will be used in your group.