You need to be cautious and rational about bringing a dog that has had previous trauma into your home when you have kids. You definitely need to spend some time with this dog and get a clear picture from the shelter staff on it's behavior. It might not be the best fit for your family or the dog. Some dogs who have had trauma get nervous and anxious easily and don't do well around little kids. Also if the dog gets scared you don't want it lashing out at your little one.

When we adopted our dog from the humane society my wife spent a couple hours sitting with her and taking her for walks etc. Then when we got her home we introduced her to my daughter (who was 4 at the time) slowly. We let the dog get acclimated to the house. Also we have a nice space for the dog in the main bedroom in a corner with a dog bed and blankets so if the noise of having a little kid running around gets to her she can just go lay down. She also loves to sit on the deck in the summer time to escape the chaos of the house.

She is very docile with people, doesn't like other dogs much so that's also something to consider. If you are walking with your little one you want to be keeping a close eye on them and not on the dog. Our dog is trained well now but at first she wanted to bark and growl at other dogs she saw. Now she knows just ignore them and keep walking.