1. How much?
Unlimited
2. From where?
Anywhere
3. How qualified?
Anyone who thinks they can find a job
4. From which ethnic groups?
Does not matter.
5. Special preference for persecuted ethnic groups?
None. If they are persecuted, they will probably want to immigrate more than others anyway.
Very idea of immigration is silly and meaningless in world of internet. Geography based politics and law is stupid and does not make sense.