Perhaps we can say that all the people of China, regardless of ethnicities, are descendants of the Yellow Emperor. The Han people by [supposed] bloodline and the other ethnicities by political and value participation.
Also, in a democratic China, provinces would be free to have their own provincial identities, laws, flags etc insofar as they do not contradict the overall [democratic and inclusive, the way Dr. Sun Yat Sen intended it] Chinese identity, law and flag.
So we can have for example the Manchurian flag flying in its proper position relative to the Tianxia-Huaxia flag.
In other word, other ethnicities would be 'adopted' into an inclusive and democratic [political] Huaxia identity without renouncing their own ethnic identities.
You can be ethnic Uyghur and political Huaxia at the same time, so long as you hold to the same values and participate in the political life of the nation.