My specialty is what the research shows to be safe and healthy birth practices. Among them is putting babies skin-to-skin after birth, provided, of course, the baby doesn't require immediate nursery care. The babies' adoptive parents could put them skin-to-skin, no washing necessary--in fact, washing could chill them, although they could be wiped gently to remove blood or other secretions. To preserve modesty, the adopting mom might want to put on one of the hospital gowns like a robe with the opening in the front. 

One more thing: if this isn't already routine practice where your daughter will be delivering, insist on waiting until their umbilical cords stop pulsing before clamping them. Early cord clamping deprives infants of a substantial proportion of their blood supply, which is good for full-term babies and crucial in preemies, which twins are more likely to be.