The idea of ethnicity and nationality doesn't really play a prominent role in any Chinese dynasty up until the modern Republican era (beginning with Sun Yat Sen's idea of a five unified Chinese races).

In fact, many of the dynasties you mentioned, especially the early Tang dynasty were especially extreme closely tied with Central Asian tribes. The Tang were especially known for incorporating many aspects of their nomadic background into "mainstream" Chinese culture and government policies. For example, many of the early Tang emperors were known for being especially martial; the Tang Dynasty was also notable for their relatively "liberal" views on the role of women in government. The early Tang is the period in which traditional Central Asian and Middle Eastern games were introduced to the Imperial Court, with many female courtesans even engaging in games like polo. Furthermore, Wu Zetian, the former concubine of both of the two preceding emperors, became the first and only Chinese emperor.

So, there's not really too much information on how "non-Han" people were treated during many of the dynasties, as far as I'm aware. On the other hand, in many writings, such as those by Tang official and writer Han Yu criticized Buddhism, one of the three major Chinese belief systems, for being created originally by a "barbarian".

As translated by Giles in Gems of Chinese Literature:

Your Majesty's servant would submit that Buddhism is but a cult of the barbarians, and that its spread in China dates only from the later Han dynasty, and that the ancients knew nothing of it.

...For Buddha was a barbarian. His language was not the language of China; his clothes were of an alien cut. He did not utter that maxims of our ancient rulers, nor conform to the customs which they have handed down. He did not appreciate the bond between prince and minister, the tie between father and son.

Furthermore, during the Tang dynasty, there was a significant foreign population living in coastal port cities, especially in Southern China. During the period of turmoil surrounding the last days of the Tang, groups of desperate peasantry sacked and looted these cities and notably slaughtered the inhabitants of the foreign/international districts (Morton 124).

So, basically, my theory, based on the sources I'm familiar with, is that the ancient Chinese were more accepting of groups that possessed "mainstream" Chinese culture, rather than dividing on cultural lines. As the whole basis of the Tang education system and Confucianism as a whole was using the literature of ancient thinkers (e.g. the Four Books and Five Classics) to educate the young in proper morals and behavior, any cultural sources other than these ancient thinkers was probably not too highly viewed by the Confucian-educated scholarly class.

Sources

Don't have access to my literature database right now, so I mainly drew from the information in Morton's China: Its History and Culture (for the basic facts) and the primary, translated source from above.