Opinionated/perspective question: what gives a people group the right to have their own country? and what are the possible "complications"?

The group of people forming a new country should have somewhat a large amount of people, a wide variety of jobs to offer in the area, and an army/militia powerful enough to at least defend itself. It must also be regarded to other countries as an actual country, or else it is not one. Some of the complications that could occur when forming a new country is the acceptance of other countries. If no other country actually accepts it as it's own nation, it is not a nation to the eyes of others, meaning it it not a country. More complications would be land, as you should have a formidable amount of it, and again, it would not make it a real country. Another is simply not having a powerful enough army. Although many other countries have weak armies, if you were to start off a country with one, it would not be a "country". 

Hope this helped you. c:

There can be more freedom for them

Cpopulation density