I’m concerned that the university or external examiners of my dissertation might not agree that the type of scholarship and content of my dissertation are appropriate for a PhD degree. Is there anything that can be done to lessen that risk?

If that is a concern, it would be important for you and your supervisor to keep the G+PS Dean’s office informed of the progress of your research and plans for its inclusion in the dissertation, so that advice could be provided throughout the dissertation work, rather than just at the final submission stage. The G+PS Dean's office can provide a rationale for and description of the program to the examiners if necessary.

It is also – always – important to provide a rationale for the merit of the work more generally within the body of the dissertation.