I found that the lanolin I used for sore nipples helped my lil guys lips stayed soft too.. if it's safe for them to have on their lips to BF I don't see why it wouldn't be ok for chapped lips too.
As far as I'm concerned, Aquaphor cures or improves any skin ailment. I used it in my son's lips a lot when he'd get nursing blisters (I checked with the pedi first to make sure it was safe on the mouth-- it was.)
Re: chapped lips?