I'd find a good book for her, like Pinky McKay.
You could go deep inside and find the place that houses ll your concern for her wellbeing as a new mum and her new little person's wellbeing and start off by saying "See, the thing is, with these things you think will stop your child being a brat, they are the things that really make a kid think of only themselves and how hard done by they are and turn them into mistrusting teenagers", then back it up with a book that says the same thing or back up your words with things you've read about why CIO is harmful to babies, separated sleeping goes against mammalian evolution and the physical act of breastfeeding builds neural pathways stimulated only by that touch experience. You can go through how no matter how much she wants the baby wants to bond with others, the baby will only readily do so when s/he is secure in her/his relationship with the mother, and that requires all the spesh love, nourishment and holding that she can give, for free, and that will also protect HER from PND, stress and the emotional drain of listening to your baby cry unnecessarily.
Young mums and career woman can be the toughest nuts to crack with the 'surrender' message - to get across that surrendering to what a newborn brings to your life is actually ok and instead of putting a dent in your life, will enhance it with the people skills it brings and the sense of human understanding that can dawn on you if you let it. All the stuff you already know, Lily!
She's asking you because she likes something or a few things about how you do motherhood. What you need to balance here is the wording and timing and what you know. On no account, please, short change your friend and tell her only what you think she wants to hear. Leave your door open and shoot it straight (and empathetically, of course!). She has invited YOUR experience and knowledge xxx