Of my 5 greys, I've had one who loved kids, one who was slightly afraid of them but behaved ok, and 3 who pretty much ignored them.
Welcome in advance to being an aunt! It's wonderful! When my niece was a baby, greyhound Eve adored it when I babysat. But Eve gave me the evil eye if I let the baby cry. She wasn't bothered by the noise, she was bothered by me not attending to that baby.
I've seen other GT posters say they have had difficulty handling a baby buggy and dogs on walks, but I never had problems. The dogs walked single file on my left. At first I muzzled them on walks because they were right at eye level with the baby in the buggy and You Never Know, but it soon became clear they were fine.