Other than "duplicate this screen" will there be the option to build screens with common elements: headers, footers, navigation
And/or will there be an option to include common elements that can then be edited and saved across all instances?
1) You can get this to some extent if you use screen states to show changes to a screen. This help topic will help a bit explain that. Look at the "flow of changes" section.
2) Yes, you can vote on that here if ya like.
A lot has been going on since you wrote. I'm glad to tell you that our current version supports reusable components - screenparts -. In this link you can find more information about screenparts.
Once again, thank you for helping us make Indigo better. If you have any questions or more feedback about the product, we'd love to get your thoughts.
Best regards,ClaudiaIndigo Studio Team