So I was wondering, with the Friend Safari in X and Y, you get the third pokemon if your friend has beaten the league and get a hidden ability if they're on at the same time, but do any of you know if that hidden ability is just for that third pokemon, or for all three?
You don't need to be on at the same time to get hidden abilities, the only thing meeting them online does is unlocking the 3rd poke if they already beat E4. And they all have a chance to have their hidden abilities, it's just somewhat uncommon. But it's still easy to hunt those if you got something with Trace to check before catching.
Actually, you've got it a little backwards. You can meet the third pokemon without having them online at the same time as you, since I did it the first time ever with Cat's friend safari, not too mention serebii has got the details as well.
Yeah, you don't need them to be online at the same time as you, I meant you just need to have been online at the same tme as them at some point after they've beat E4, afetr that the third is always there.