Socializing puppy with toddler.

You are 100% correct to want to do this early with a puppy. Here is what I do...

1. Exercise and play with the pup for a good length of time to get their tongue wagging and all that energy out.

2. Then feed the pup.

3. Then I like to put a leash on a flat collar on the pup, and put the toddler on the floor by puppy. This works best with two people, one over toddler and one (you) over puppy with leash loose, but ready to restrain. Have treats too. Then, watch the pup closely. If he crowds the baby, or gets too excited calmly pick the pup up and move him back a bit. Calming voice, calming petting (slow long strokes). Every time puppy is calm and interacting nicely praise (calmly) and treats. I was so grateful to have a friend that was willing to let me socialize my pup with their baby. Now, both young child and young dog know how to act around each other and love to be around each other.

Kudos to you on this one, this is one I'm really kicking myself for, Ava's first interaction with a todler was just the other day in the vets office. There was a nose bump (it was more of a binky to nose bump), the girl cried and Ava just sat down with a really confused and concerned look on her face. She really had no idea what made that funny looking and smelling puppy yelp and keep on yelping....(no one was hurt, just startled) my fault, I guess I have forgotten where to go to find little ones.......mine are grown.......lesson learned, now on to fixing it.

Fortunately I come with my own built in human little people. LOL
BUT....to get my dogs used to other kids, baseball season works wonders.
We got Angus last April, maybe 2 weeks before the boys' t-ball and baseball seasons started.
He came to every practice and game through the season. It starts up again in 2 months, and Reich will be coming same as my boy did.

It's great because there are always siblings too young to play the game running around who can't resist a puppy.

i'm not sure how to socialize puppy with OTHER babies, because our puppy has only been around our daughter, but she is very good with her. our daughter is one, & the puppy is nine months & our daughter will crawl all over the puppy & yank her nose, she even poked her in the eye (did it before i could get her away from the puppy) & my husband & i froze cause we thought she'd nip her, but she just sat there like whatever.

i've read they are great family dogs. gl.

That was real good advice about getting them tongue wagging tired.
My grandkids are not exactly toddlers, 5 and six year olds, but they had never been around a puppy at all. I allow gentle chewing on my hands for play with Mack. It's just me and him and I use it as bite inhibition training. Well, what is gentle to me and a 6 year old little girl is obviously different. The first little nip you'd have thought he had tore her hand off. I had actually been getting very good results with a stern, "No biting!" when I didn't want to allow it and told her to say it. She did but it lacked much authority and conviction. "That's how puppies play." was little consolation to her. Between the jumping up with the sharp little claws and the nipping, she wants little to do with him now. Probably doesn't help that her Mom is terrified of any dog.
Anyway, until he gets out of the very young, chew on everything, puppy stage, the "dog tired" idea sounds like the way to go.