thisguychicity
The issue at hand is that none of these roles is ever really done. It's very likely that someone will up and vanish for one reason or another while the company is being built and the remaining founders will have to bring someone else in and offer them equity to pickup where the previous person left off. Ensure you have take with and come with provisions for the protection of all shareholders.
Details: I would form the company as a corporation in Delaware with more shares allocated than distributed. Base your vesting schedule off of the shares allocated and not the possible number of shares distributed. This gives you the ability to sell shares to investors without having to pay a lawyer again in the future.
Source: Done this a few times and sold two companies in the last six years.
Me - http://www.strapr.com - happy to provide more advice if you want some, my email is on there.
Disclaimer: I am not an attorney and this is not to be construed as legal advice, you should seek counsel for your needs.