I just came back to the boards after a year's absence… And we've had a baby who is now four months old (see pics under the Cooper update thread on show off your dog).
Things have gone really well for us, but we worked hard at it. It's great that you know he's already good with kids and babies! Start thinking right now about how your life and routine are going to change, and get Zumi used to some of those new things:
-Let him see/sniff everything that comes in for the nursery, and set limits of what he can play in/with (you should discourage any further use of the bouncy seat).
-Start sitting in the rocker/chair you'll be using with the baby. Set up a nice cozy dog bed nearby. I often nurse on the couch or propped up in bed, and Cooper loves to curl up by my side and enjoy quiet cuddles.
-See how Zumi reacts to you fussing over a baby doll and ignoring him or to hearing baby cries from the crib (rig up speakers or a laptop). Work on desensitizing him if needed.
-Think about all the things you will have to do for him one-handed! Can he sit for you to put on his leash? Is he a good walker? Will he sit for you to stop and tie your shoes, check the mail, or greet another person on a walk? Does he know a command to go to his bed or crate when you need him out of the way? Does he know a "leave it" command? Is he scared to walk by a stroller (you can practice with a shopping cart at a pet store long before you purchase a stroller)?
-Think about his safety! Cooper seems to be fascinated by disposable diapers, but doesn't care a bit about the cloth ones we usually use. The absorbant gel in disposables can kill a dog if ingested, so be careful with the diaper pail.
-Walking is great exercise while you're pregnant, and very enjoyable for your dog. Walk, walk, walk! Incorporate obedience work into your walk if you don't already to make life easier. Put a good ergonomic baby carrier on your registry (Moby and Ergo are safe and comfortable), so you can walk the baby and dog and have both hands free.
Hope this helps!
Ruth