Will,

Well, I have some ideas. You could group them in 3 categories:
1. Focus. I think you, and team/partners/community, have to focus. What are the goals? I think it's, from a software engineering perspective, wise to build and market this product as E-Commerce and NOT CMS (I think that would be very wrong, probably there are legal issues (but we don't know, and everything is MIT (?))).
2. Community. A community is important. You'll have to convince these stakeholders to further build the product and at the end your own business. Using the already D.N.N. community is the way to go.
3. Don't reinvent the wheel again and again. Because of the new way of developing (Web Api and JS (React or NG) components) it is simple to incorporate your code within the great part. So, let use 9.1.1. as the startpoint and further develop Hotcakes.