No, you need an easy-access demonstration of what your app will do, including the most important features and differentiators. My wife built her prototype with cardboard and paper and I watched potential investors and partners light up in the first 30 seconds as they played with it and understood right away what she intended to build. Mission accomplished!

I need a ticket sales tool. Something much simpler and more usable than eventbrite. Preferably one that integrates with stripe.com.

I don't think there is a role. I think you need to determine the responsibilities and motivations a person might have for sponsoring and speak to their needs related to it. In my experience, the people with these interests in a company don't reside in just one role.

Tell the story of the problem that it will solve. Build a community of people who care to have that problem solved. Keep them informed of each step of the road to build the solution for them and get their help building it. Then when it's ready you have demand, a customer base, and a community that will attract others.

Confidence that you will achieve your goals and return money to them is what matters most to investors. Confidence that your team can make that happen is #1. Why will you be the ones to succeed at this?

Co-founders are permanent, long-term members of your team and a technical co-founder is someone who has a long view of the product's development, is committed to seeing it happen, and can make it happen. If you don't need that, sub out.