I think you're right about discipline being different to do properly for highly gifted kids. On social development, it's bound to be a little different for kids placed with much older academic peers. I don't know if it's necessary to cater to social development differences if there aren't any problems, though.
What do you mean by family structure differences? We don't have set bedtimes, and allow DS5 a lot of autonomy. I think I'd be that way with a normal kid, though, on the same grounds: if he's up learning at midnight and doesn't want to stop building or whatever, I'm not going to stop him. I think you must mean something different.
