I think that is a really tough decision, I'd really want them as a total package!
I think that Peter would probably be the brother I've always wanted, protective
and mature, but, now, SKANDAR (not Edmund, really) would be amazing as a brother,
I know we'd have so much fun because we're both completey spastic and everything.
It would be great either way. I think overall Peter/William because I'd like to have Peter as a brother, and have William as a brother, whereas with Edmund/Skandar, I wouldn't mind having Edmund, but don't really need him either, but I would love to have Skandar as a brother.
I also think that Corin would be a BLAST, even though he's not LWW, he's just hilarious.