I think adopting two from the same litter can lead to a lot of trouble as they've been fighting for resources from day one, and often they continue their whole lives. It's often better to get puppies from two different litters if it's two you want.
I just call mine a farm dog bitsa most of the time. She's not 100% Cattle dog. Bits of other farm dog there, but which I don't know for sure.
I figured - for my sanity, it would be best to get the second dog, when the first one comes when called reliably. Ie the older dog fetches the younger one back. You don't want the older one teaching the puppy naughty things like ignoring the boss.