That really is not how Tesla works. They have no ability to coordinate with a builder.
My $0.02 is build your house, plan for the solar roof, but put up a real roof one, and then after your home is built and occupied, ask Tesla if they would consider putting on a solar roof in your location, with your as built roof complexity. Having a home with large simple roof planes will help, but if, and only if, Tesla installs in your area.
So, yes, you may end up paying for more than one roof, making the Tesla solar roof even more expensive.