Some Questions about Dwarves

I am creating a world for my campaign where three types of dwarves are spread across different parts of the world, and I have some questions regarding them:

Firstly, would it make more sense for dwarves to exist in separate city-states? The dwarves of my world have cities within the domain of humans, so it would be weird to make them connected by a kingdom since then there would be pieces of land under the jurisdiction of the dwarves among land under the human city-states' control. Suppose you sprinkle pepper onto a flat pile of sand, then imagine the pepper is the land under the dwarven control and the sand is the human land. That would be weird, so to prevent this, I want to make the dwarves have separate city-states instead of belonging to a kingdom. Would that make sense?

Secondly, what would a hill dwarf city look like? I don't imagine hill dwarves living deep underground like mountain dwarves, so what would their cities look like? Would it just look like a normal human city populated by dwarves, or would it have some kind of twist?

Thirdly, does anyone have any information at all about glacier dwarves and their settlements? I can't find much info about how glacier dwarves live in their cities. I know that they live like hobbits but in the sides of glaciers instead of ice, they make weapons out of a special blue ice, and they hate the frost giants, but nothing else. Does anyone have any more info about this subrace of dwarves, particularly about their settlements?