See Topic Title.
This is not just a topic to ask for asking. I seriously don't know which to choose. I assume morally I will pick two kids from the street as the from the orvanache already are having a roof over their head.
Aside from that: Grelof is dead already so these kids should be happier now.

Grelof uh... has passed away. Old age most likely.

I'm a PS3er, so I don't have anyone yet. My Dunmer lives in Solitude, so she'll be mommy to Blaise and one other, maybe Lucia. My Imperial lives in Riften, so he'll adopt Runa and one other orphanage kid. And my Nord can't handle Astrid but wouldn't do random murder either, so she'll go with street kid or two. Maybe Sofie and/or Alesan.

Beyond that, the following might help:

http://www.gamesas.com/topic/1423060-an-interesting-take-on-skyrims-adoptable-kids/