You are expecting to need more than you actually need. You are thinking like a larger business, it appears.
You basically need
Basically the organizer is someone to help ensure that everyone is on the right track, as it is easy to start going off on a tangent, at times, and losing sight of the immediate goal.
Once you develop a product and start your beta testing then your developers can start to do some documenting, since users won't read anyway.
A good article about that is:
Business development in the beginning is pretty simple. Go to production, sell.
Later, as you get larger then business development may be more needed.
Marketing will do ad sales, but, unless you have lots of funding, you will probably do little in ads, and try to be more creative in how you get the word out.
Your best bet may be to develop a relationship with an independent recruiter, as you can then develop a bond, so as you get larger, you will go to him for your needs, so that he can benefit from helping you, as he could be part of your team.