Yep, good points.
You also wonder, what sort of government, what sort of social structure, would there be on this spaceship. Who would do the work? Would there be money, or a government? Would children go to school at all? How big is this spaceship? Would it be like being packed in an airplane? Imagine living your whole life in some confined space.
In Gene Wolfe’s Book of the Long Sun they don’t even realize that it’s a ship. It’s one of those giant cylinders that they spin to simulate gravity and the people live on the inside.
https://en.wikipedia.org/wiki/The_Book_of_the_Long_Sun
Freegards
A planetoid with tunnels, caverns, farms and factories, hospitals and academies; all safely beneath the surface. A world unto itself.
A very tightly controlled society broken into for or so exogamous clans but all subject, of necessity, to restrictions on childbearing and employment.