How are minorities treated in China today?

Ethnic minorities get preferential treatment in some ways, such as exemption from the one-child policy to encourage their population to grow.

Just as you have various ethnic groups in multicultural countries like the UK or US, Ethnic groups in China consider themselves to be "Chinese", instead of identifying themselves as separate groups.

Do you mean the indigenous tribes?

They have sometimes more right than the Chinese.

They can have as many children as they want, for example.

The minority languages are also recognized.

However there has been reported discrimination of the Uyghurs, by the Chinese goverment.

mainlanders sometimes sees foreigners as rich depending on where they are staying.

in general, minorities will get stares as it's uncommon but it also depends on where. if it's the main cities like beijing, shanghai and guangzhou then u won't get much stares.