I'm glad that this came up. We have tried as mch as possible to let Boydog and Girldog know that little Ff is part of the pack (yes, I do subscribe to this theory, mainly because following it has worked for us), and have never excluded them. As far as was possible, their lives haven't changed since she was born. (She is 11 mo, by the way.) They still get walked twice a day, they were not allowed upstairs anyway, and still have free run of downstairs, including the sofas. (Because what is the point of having a dog if they can't act as teddy bears/foot warmers?)
They have always been allowed to investigate her - Lotster, we put the carseat on the floor when we brought her home and let them sniff. Boydog got excited whenever she made a noise for the first week, but that soon passed. I was worried when she started playing on the floor, but they always seem very aware of their size and bulk, and give her all the space she needs.
Boydog isn't wary of her, but takes himself away if she moves towards him, or tries to stroke him. He is a very gentle dog, and often gives her a sniff and a lick when passing, but seems to prefer not to be bothered by her. Girldog, on the other hand, is her best friend. Ff first pulled herself up to her feet using Girldog's collar, and loves patting her head, or snuggling up to her side. All of this conatct is, of course, closely supervised, but I have been surprised and touched by how two huge dogs appear to modify themselves in order to be gentle with her.
I wouldn't leave her on the floor in a room with them if I wasn't there. They are only two and three, and still prone to sudden dashes if the door goes, and while I am confident they would avoid her, I wouldn't take the chance. When she is in her walker/chair thingy, I do leave them alone briefly, but only because I am 99.9% confident in them, and we have ahd them since they were puppies, so have been responsible for their training and can reasonably accurately judge their reactions. Neither have ever reacted violently to provocation, even from quite fierce seeming dogs.
However, I tend to banish them if other babies/children come to the house, purely because they are big, and young children are unpredictable. It isn't fair on them to expect them to behave as well as would be required with children they do not know.
And, as some of you probably know, they are rotties. Gentle, intelligent, and impeccably behavioured rottweilers.