Interesting questions, let's address them in line:
1) As far as nutritional "needs" her protein requirements have increased by 25g/day (depending on the source this will be about 75g/day). Additionally, the current recommendation is to have mom take fish oil at 300mg of DHA/day.
2) With respect to weight loss and dieting post partum, it doesn't really appear to affect milk output quantity or quality until caloric restriction is marked (<1500kCal/day).. Losing weight does not appear to affect lactation either. Most medical literature suggests that breast feeding "burns" an extra 500kCal/day, but as you know there are multiple inputs that the BMR reflects- thus, I would say this recommendation is "soft" at best
3)I can't accurately recommend macros because I don't know what she's doing now, macro wise.
4) You're definitely going to want to talk to her health care provider about sleep issues post partum.