John: Always smiling whenever he holds him/her and begins trying to make out college plans.
Paul: Attempting to teach the baby (who most likely was born a day ago) how to talk. And if he's not doing that, he's acting silly until the baby smiles.
George: After the long night, you're both very tired. George is most likely sleeping next to the baby in the hospital bed.
Ringo: Wants to go shopping for the newborn but doesn't want to leave him/her.