There could easily be interludes where the adults influence the children in secret (like in Ender's Game), but unlike Ender's Game, they could be much longer, perhaps even entire chapters. Although, the way OSC did it was kind of nice in that the characters were divided more evenly that way.

No one knew how the arches were formed, only that they seemed impossibly large and numerous for seemingly natural structures. James had been to St. Louis as a kid, and he remembered riding up one of those rickety old elevators to the cramped lookout area with the tiny windows. Looking at the Arches of Nevhal though, he couldn't help but imagine an entire house fitting insdie the girth atop one of these monstrosities. Plus the view would be far better; he thought it could rival the view from his friend's condo in the Birge Dhubai, which he had been lucky enough to visit one summer back in college. 135 floors up is nothing to scoff at.

I don't know; that went pretty well actually - didn't take much time, flowed easily, isn't utterly bad / poor quality.