I asked this question elsewhere and got replies saying to spray the dogs in the face and to knee them in the chest. :O NO WAY I would do that do my dogs. Im not just being overly sensitive, right? How would I find a pro trainer who wouldnt do those things?
If you interview trainers and emphasize that you're only interested in positive training techniques, you shouldn't have too much trouble weeding the ones who use punishments. You should only need a couple consultations to help you with coping mechanisms for when the kid starts walking. Check out the facebook pages for trainers in your area and see what sort of articles they share, most will share lots of pro-positive articles if that's what they believe in. At least, the ones I know do!
I agree that giving them an outlet will be hugely beneficial. I think your instinct on giving them the "sit" command instead of "off" is a good one, since most dogs have "sit" ingrained pretty strongly. Just make sure you're prepared to praise/treat appropriately.
With a baby it's obviously difficult but maybe a friend or family member or your partner can take them to agility classes or even set up a small course in the yard or something? A basic agility course with a pause box, weave poles (used ski poles jammed in the ground work), a couple pylons, a broom stick over a chair, etc can be fun and give them a break from the every day stuff. Also, food puzzles/toys might help. They might be feeling a little under stimulated intellectually, especially if the baby coming has meant a major change in their schedules/exercise levels/whatever. If they haven't done the herding aplactions to kids in the past, there might be a jealousy/resource aspect to them doing it to the baby, either in that they're jealous that the baby is getting your attention OR that they want to interact with the baby and don't understand why you always get it to yourself! That's something that would be more easily recognized by a behaviourist seeing the behaviour in action but it's something to keep in mind when watching other patterns where the baby is involved.
I'm not sure about your personal situation but I always recommend this book to first time parents with dogs: http://www.amazon.com/Living-Kids-Dogs- ... 1933562129
I saw Colleen Pelar speak at a seminar and she was excellent.