well, the security and founders need of the refugees is a bit vague. especialy because the security wouldnt be really needed if they eliminated the resistance completely, so they would be free to do any maintance work needed.
Exactly. People that are fixing problems that are created by their very existence don't seem very "needed" to me.
"Their numbers are too small..."
But again, who's to say that the extraneous stress on the infrastructure and system due to being overpopulated isn't what's making all that work necessary to begin with?
Edit: Didn't see you previous post. There's also no way of knowing how much they stress the infrastructure outside of Container City. I assume they travel to other areas of the Ark. I would also think they have the provisional systems working overtime to accommodate the exploded population.