The thing is that child Ikki is more open with his feelings per say and even more of a protector than he is as an adult (or shows it more, whatever) so if there's a child Kotomi running around there will be lots of "touch my Kotomi-chan and you're dead!" at whoever dares to even stare at her.

Well, Yoh could use a sibling that isn't aiming to kill all human beings by becoming God for once. What age was Madoka?

One wonders who will be the one taking care of whom regarding Natsuno and Goku... I can see Goku hugging his lil'brother while Natsuno just linefaces forever XDDD