I have cockers and have my whole adult life.
I would suggest working on the dog being independent ASAP. They can be velcro dogs. Which means they can get jealous when a baby come along.
Work on making sure the puppy is happy to be shut in another room, for short periods if you need.
Make sure they are used to baby noises. Play them from you tube on your phone.
Also make sure you work on trying to prevent resource guarding. They can have a tendency towards resource guarding.
Make sure you have a plan in place to walk and mentally stimulate the dog. Even on days, you are struggling with the baby, this needs doing. The last thing you need is dog that has excess energy and wanting attention, if its a bad day with baby. It will make everything worse.
That said, the 2 I have had when I had my babies were both great. I havent ever had resource guarding issues, with mine. And both seemed far more interested in sitting somewhere they could see the baby from, rather then bothering with me in first few months.
But mine have all been older. But I don't want you to think I am trying to put you off. I love spaniels. But it will be tiring.