First of all, I don't believe Chinese are 90% Hans. Whenever race is brought up people with mixed races are screwed and in China that is a tremendous number.
Do you see Hawaii and Alaska got screwed? If not then Tibet and XinJiang will not be screwed. Let's replace CCP with a real republic goverment and discuss Tibet's independence later.
LOL. Why not ask the original inhabitants (Native Am's) of Alaska and Hawaii? They might give you a different spin on whether or not they got 'screwed.' The same applies to Tibet.
As for Tibetans not wanting political independence because they have 'religious independence' is ridiculous. Why, then, is Tibet pretty much one large PLA base? Why do they have to put down riots every five years or so? Why are 100,000+ Tibetans now in exile?
There can be no religious freedom without political freedom, especially in Tibet where the two are so intertwined (for good or bad...)
As fot Tibet being part of some republic, why should they? China's claim on Tibet is about as historically based as their claim on Outer Mongolia and Korea!