Tire him out. Start instilling manners- this is the prime age to start molding them into house dogs by practicing things like NILIF (Nothing In Life is Free). Puppies at this age have zero impulse control and a LOT of energy. They also get really wound up if they're over-tired or over-stimulated, so a crate is going to be your best friend when it's time for a puppy nap.
I would be really, really, really on top of the puppy and the baby together. Like, 150% with supervision.