I really just trying to learn more about how the Debian Installer works so that perhaps I can contribute in the near future as well as learning how to achieve the goals that I am trying to accomplish by being able to simple add a package to learn what it takes to achieve that objective. My estimation is that the mailing list along with reading all of the information that I can find (i.e. D-I wiki, etc...) should be a good start towards that path.
Is the requirement of the D-I that all core packages come from uDEB packages?